People don't know about these links because the main website does not publicise them. Instead, every effort is made to send the user back to the online installer page, which, tries to do something unnecessarily fancy that does not work on many machines for no obvious reason (for example, it often does not work in Windows 7/Vista/XP with any version of Internet Explorer).
When you try to find an offline installer on the Adobe site, you end up being directed here, which does not have it:
Ditto for Google.
So really, the people in charge of the website need to fix this because it is very frustrating and it is absurd that the only way to obtain these links is to come to a post such as this on a forum.
It is so bad at present, that even when you select the option of downloading Flash to install on another machine, it still tries to do the fancy stuff that doesn't work as if it is trying to install it on the current machine instead.
unfortunatelly, also those steps offer online installer