The 'everything you build as a developer is extremely temporary' was something I had to learn over the years. I used to make video games, and I grew up being able to play my old games no problem, but now nothing is physical, everything is sandboxed in an app store (or intrinsically glued into a website) and disappears the instant the company disappears, or moves on to a new project, unless you work on a major title.

And even if that weren't the problem, there's such a firehose of games getting released constantly that people no longer value them, and move on to the next game after barely spending any time with the existing one, unless you intentionally manipulate their psychology with some free to play garbage.

That's part of the reason why I now feel so drawn to board games, as they at least still have physical boxes that can last for decades.