As long as America has Vegas., the biggest boxing shows will be always be in Vegas.
As long as the Heavyweight division is void of a good American, America isn't gonna have a vested interest in the Heavyweight division. This has a knock-on affect on American coverage.

American coverage is (IMO) vital in this sport at the moment. Even though the K-BROS are selling out areas in Germany, they are practically excluded from the mainstream (albeit HBO but that is effectively mainstream).

I mean things could (in theory) change whereby Germany becomes the hub of world boxing. And to be honest, with the effort they put into their shows, it could be a good thing... But unlikely.

So to answer your question, it's not really a matter of who's good because really how can you define good (or exciting) but it's just a question of who you can market.

I blame Rocky.

Scrap that, I blame Chuck Wepner