It depends on timing. If the camera was available for sale in a few weeks from now, you'd probably have to wait 3 months.
You missed my point. How many of the other cameras that have just been announced were included? I have to believe Adobe and Panasonic must have collaborated a month ago or so, in order for raw support to be present now. I would hope more companies would recognize the value of such cooperation when developing new cameras, but I suspect it's still the exception rather than the norm.
Added by edit - Maybe it is a trend, The Nikon D3400 made it, although the Canon M5 did not.
Second edit - One day after announcement may still be a record, the D3400 was announced in August and available in early September. It would be interesting to see a list from Adobe as to whether they had to reverse engineer raw support or received assistance from the manufacturer, but of course it will not happen, can't risk aggravating any of the companies.
Adobe won't include support for a camera that is not announced. Adobe has to have a camera in house to profile, unless the manufacturer has already done that, which occasionally happens. Assuming Adobe has to make the profile, for Adobe to have a camera in house they have to either buy one that is already available for sale or the manufacturer has to loan them one; however, that camera needs to be shipping ready, not a pre-production beta where the firmware or something else might change before it is available for sale.
The problem has always been that Adobe only releases their software at several-month intervals and the release usually includes code changes such as feature additions or at least bug fixes, so there is code-testing to do not just camera-support-testing.
If Adobe gets a camera enough days or weeks prior to release to be able to profile and test, and the camera has been announced before they release then the support will be there at release time, otherwise not.
If Adobe could release camera updates without other software changes also in the release then their turn-around could be faster, but they mix both together and that cycle time is several months.
If a camera manufacturer could always loan Adobe a pre-ship model that will be the one people buy, enough in advance of an Adobe release then the camera will be in there. If Adobe has to buy one then it'll be in the next release.
Camera companies don't wait for Adobe releases to put things on sale, and Adobe doesn't rush things because a camera is for sale.
The worst case is a sale-ready camera is not available to Adobe for testing until just after a release but the camera is for sale just after. Then you'd have to wait months until the next release.
The best case is that a camera has been announced and the manufacturer is ready to ship but hasn't and has loaned Adobe one to profile a few weeks before Adobe releases but the camera isn't available for sale until just when or just after Adobe releases.
Which one of those happens depends on the timing of the Adobe release, the camera first-sale date, and the amount of time the camera was ready for sale but wasn't sold. That last thing is up to the manufacturer and is probably not going to be a optimal for Adobe since why would a manufacturer sit on a camera that is ready for sale but not be selling it.
You mention the D3400 being included, which was already being sold a few weeks before the release, likely it was available to Adobe a few weeks before that if Nikon loaned them one. So it was close to the best case and only Adobe's release timing got in the way.
The Canon M5 not being included likely means Adobe doesn't have one from Canon and since it isn't shipping until December (according to the pre-order note at B&H), I doubt Canon has one to loan them other than a pre-production model, right?
Your long post states the obvious, but doesn't really address my point. Adobe had a production level release out one day after announce of the Panasonic G85, and a beta release prior (the samples at dp review show CR 9.7 in the metadata). It may be that the change was a trivial tweak on the G7 profile, and/or it may be that Panasonic shared info early with Adobe.
The G85 (G8 in the US) is available the end of October. When do you expect to get yours?
Near as I can tell the G8 was supposed to be available, sooner, but an earthquake caused problems by disrupting the supply of sensors so they've delayed until now. I'd guess that Panasonic had some production-ready models in house to loan Adobe, but because of their sensor supply issues didn't actually announce the camera until they were more sure when they could ship it based on sensor availability.
If this is what happened, then it's probably a special one-time circumstance that isn't going to be repeated by other manufacturers, where they have a few cameras to loan people but don't even announce the model until LR is ready for release.
It's G85 in the US, G80 I believe in Europe, and who knows what elsewhere, B&H estimates end of October.
I searched the latest Camera Raw (9.7) folder for a .dcp file, could not find any for G8/G80/G85, yet ACR works with the sample raw files I downloaded from DP Review. I also used a hex editor on the 9.7 .8bi file, there are text strings within it for G85, G80, etc. I have to assume ACR is doing some sort of internal "trick", where they detect the G85 in the image but re-direct to an existing profile. My best guess is the GX85 would be identical, same 16mp sensor and no AA filter.
If I am correct and Adobe is re-directing to an existing profile then that may explain why they were so prompt. I'll be interested in seeing if a discrete profile shows up in later ACR versions.
I moved all the Panasonic-brand DCP files to a folder at the root of my drive, leaving no Panasonic DCP files in the Adobe Standard folder and Adobe Standard is still listed as a profile for the G85/G8 test raws I have, even ones I just downloaded to make sure nothing was cached about the raw data. If I do the same thing for 7D2 raws then the Adobe Standard profile disappears from the profile list.
To me this suggests that Adobe has hidden the G8/etc profiles within the ACR binary. Since the production ACR shipped the day after Panasonic made their announcement the final beta that was released as the production version would have had to have been finalized a few days or weeks, before Panasonic made their announcement. Adobe would likely be breaking an NDA with Panasonic if they created a DCP file with G8 or its variants in the filename as that would be documentation that the camera model existed at Panasonic.
Good experiment, probably you're right on. The .8bi file runs about 66mB, each .dcp near 100kB, they could easily tuck a few in there without overly expanding the CR plug-in.
Using the hex editor I could not find any obvious trace of an embedded .dcp in the CR plug-in file. Also Lightroom is similar, no discrete .dcp for G80/85 images, but handles them ok. Not obvious where Adobe hid the profile.