I'll open saying I don't think this was a good year for Blizzard, with Diablo Immortal, Heroes of the Storm going life support, multiple high profile members leaving AND the announced cost cuts for 2019.

However, there is a large gap between a company having a bad year and they filling for bankruptcy.

Yes, I believe there is a chance this is the start (or the increase?) of a fall in quality and yes, maybe eventually Blizzard will be the new Bethesda.

But some years ago people said the same thing about Wii era Nintendo and Epic was basically the company who made Unreal engine and look where we are now.

Honestly, the focus on releasing more games instead of living off the esports dream may even be a good change. However, I question if they'll be able to release AAA+ games with a shorter development cycle. Some companies know how to work fast while keeping quality, Blizzard doesn't look like one of those but time will tell.