I think this doesn't take into account the difficulty of game development. Having made a few in my day, both smaller and larger, I can tell you that the easiest part of development of a solo-dev or small team is the beginning. Ideas and story are quick and easy and don't need to be compared with anything else that's already in the game, technical debt is near zero, quality doesn't have a bar since none has been set.Can't say I agree about the art quality declining, but you're not wrong about the slow progress and excuses. Unfortunately, this happens with literally every decent game I can think of. They start off at a steady pace, become successful, then slowwww things down to keep the money rolling in. It's just how the current system works and we haven't come up with a better way of doing things yet. We haven't even reached the point where most people are willing to have honest discussions about the problem. The very topic triggers the "fight or flight, oooga booga, must defend my tribe" part of the brain and it all falls apart.
...I did not intend to write such a long comment, but apparently I needed to get something off my chest. I feel better now.
Once a game gets going into proper development, things actually get more difficult. New problems start to arise with bugs and systems that refuse to function together, ideas start to become more difficult to generate for fear of becoming repetitive, and art has a minimum bar, which often actually increases as artists' skills increase.
That's not to mention the difference in motivation that people have during the difficult parts of development vs. the early stages. When you're making something for yourself, you can always just drop it and move on to your next new thing. When you're trying to take something all the way to the end, it can really start to become difficult. This is why so many games (and books and comics and web series) end up abandoned.