Those are really important reservations to consider! There is some risk with a smaller company like this. Though, since Framework is on their 3rd version of the FW13, and has a pretty strong userbase right now, it seems likely that they're not going away too quickly. Also, there's the strong likelihood that at least some parts would be made available by 3rd-party providers. Other users have considered this issue a lot, and there seems to be a strong likelihood that Framework would release as much of their information open-source as possible to ensure that 3rd party support continued, in the unfortunate event that they did fail.

All that said... the concern is still legitimate. A custom-built laptop using more standard parts is another way to go (another commenter actually posted a company that does that).

As for Windows. Oh man, Windows. That's a whole different ball of wax. I've become very tired of it and, ironically, my only PC that still runs it is my Framework. I've switched my old Asus to Ubuntu and my main desktop PC runs Linux Mint.

As far as similarity with Windows goes - Linux Mint is great. It took me about two months to become pretty comfortable with the differences in the OS. But support for programs I want to use is absolutely a problem -- not one that the developers of Linux can fix, it comes down to whether the software designers want to take the time to actually develop versions that suit Linux. The good news there is that the market share for Linux (as a consumer OS) is rapidly increasing, and we're even seeing government adoption in some places, so more and more companies should start developing for it.