But I have a hard time believing that someone with the right funding and motivations couldn't come up with a solution that wouldn't depend on clients to continuously cannibalize their own holdings.

I don't find it hard to imagine that systems can get stuck in tragedy-of-the-commons traps where it becomes hard or impossible for individual actors to fix things. I'm not sure there's a person on the planet who has the resources to implement changes who would have the motivation "fix the Steem ecosystem". Why would they? They could probably do more good more profitably somewhere else.

I think that improvement is always possible.

I think improvement is possible, but you might be working on "let's invent a slightly-less-unhealthy soda for people to drink" when "drink water instead" is categorically better for that goal.

There's another wildcard in the mix, too. In about 1-2 years, we start to expect an increasingly sharper decline in creation of new STEEM per day.

I'm guessing it won't matter, subtle macro effects tend to be small so I think other factors will tend to dominate.