Kindle lock-down is 100% the fault of Amazon; they want to make sure you can only buy books from them.
I am afraid that the only solutions I know are not to buy a Kindle; or give into Amazon's tactics and buy all your books from them.
I often criticise the Adobe DRM infrastructure; but in this case Adobe is faultless.
There is something you can do! Go to http://calibre-ebook.com/ download software "Its Free" and it will convert any ebook you have purchased and then you can tranfer it to your Kendle. I had to do this when I bought my Kindle about a month ago.
Very good point. Calibre is an excellent piece of software (much better than ADE to my mind) and good at converting books, eg to Kindle format.
Unfortunately, Calibre will not handle DRM books (neither Adobe DRM nor Kindle format DRM), which rules out almost all bought books and library books.
You can go via a DRM stripper such as epubee. The exact legal boundaries of drm stripping are unclear and vary from country to country, but from everything I have read it is legal for personal use in the UK and US. It may violate the t&cs under which the books were sold.