UBBCode is disabled for new user accounts, to discourage spam (no clickable links, etc). Separately, there is an issue editing long posts, which I've been meaning to look into. I think if you move half your first post to the second it should allow you to edit it without timing out.

I do not currently play games on Linux. I have dual booted in the past, but in practice didn't boot into Linux very frequently. I'm seriously considering building a dedicated Linux computer soon, though (how soon depending on whether or not I have any money after I do my taxes and replace a monitor that died a couple weeks ago).

get funded and then put major things like Linux support on the back burner

It was put on the back burner, along with Mac, before the kickstarter. It was only once the Kickstarter goal was met that Larian officially confirmed there would be Mac and Linux versions, and Mac development was started again. The Mac release was expected to be with or not too long after the Windows release, with the Linux version to start after the Mac version was done (which was expected to be not much extra work at that point).

despite how they treat the community

You say that like the delays were a choice.

I think it's a very clear indication on Larians priorities to see their Linux port still unreleased.

If you were betting your company on the success of a game, and almost all of your development experience was with Windows, which platform would you prioritize first?

Choosing a middleware without clear Linux support indicates that Larian had little regard for for the Linux port from the beginning.

You mean as oppose to just having no experience developing for Linux? If Larian had little regard for the Linux port, they wouldn't have made the tools to replace the middleware assumed to exist, but dropped the port or used Wine.

Would they even consider choosing a middleware with questionable Windows support and then use that as an excuse for delaying the release on that platform!?

The Windows version was delayed, multiple times. In fact, Larian delayed it as much as possible (scrambling to get a loan to pay off another loan that a bank getting cold feet called in, and deferring paying taxes, then getting caught by the government changing that policy).

At that point it looks like Linux support abandoned, because:

The last couple game updates were also in an 'old' branch, with specific changes and bug fixes being moved from the main branch. After the 1.0.252 update, everyone moved over to working on the most recent set of code.

what about this "new" branch?

As of mid-March, the ETA was "some months".

So how was their small Linux team involved in this "*cool*" (so cool that it breaks other platforms is OK?) thing in the new branch?

It isn't a case of breaking platforms, but of how much time it would take to support both. Would you want the 1.0.252 Linux version around the time of the next Window and Mac update, and then another delay of "some months" while the engine was updated again with the new code? Unfortunately, updating the Linux engine to code that is already outdated isn't practical.

Though 15 years is a tough record to break

Year long delays are quite common in game development, though.