Reddit has hundreds of millions of users and the platform is highly active, making it suitable for pros to submit work for profit. Or as a means for amateurs to break in and see if they can build an audience.

Reddit is a business plan for many creators. The large audience there gives submitters incentive to put up with the horrible abuse they face from poor moderation and terrible users. And still, as you note, OC creators flee. Comparing our relative numbers of fleeing contributors per capita as being similar to Reddit isn't the win you seem to be arguing for.

Look, when some of the largest communities don't see posts for weeks, that's a sign something is wrong. We have disincentivized contribution to the point where stagnation has set in. That's a clear sign some change is in order. What that change should be, I don't know. But simply refusing to accept these clear signs as doom and gloom leads to refusing to recognize a problem. And if you don't see a problem, you can't act to fix it.