Realistically, this stuff ought to be self-evident to anyone who's not stuck in "me me me" mode. I am not saying thatto insult you, it's just that I hear way too often on this forum and on Facebook, people talking about the "reasons" for pool failing as a sport in America, and attributing it to stuff like cost of streams, etc.
There is one reason, and one reason only for pool failing in America, and elsewhere. The main demographic all competitive sports/games rely on... Young, competitive males..... Is doing things other than playing pool these days. They have no pool halls they are allowed in... And competitive video gaming, with prize funds, is a thing. And it costs much less to both git gud at, and to compete at, than playing pool.
I very much think that misattributing the lessening popularity of pool to areas that have no real relevance is destructive, and counterproductive. If we can't identify the real causes, we can never address them and try to correct them.
Young, competitive males simply have many other entertainment/competitive alternatives that are a heckuva lot easier to access than a pool hall these days. So, as older players die off or leave the game, there is no one to replace them. It's not rocket science, and it has nothing to do with the cost of a single pool stream.
Pool is still relevant to some extent in Europe because of the extremely organized, tiered league system in most European countries, that provides a structured way to compare yourself to the next player. But even here, participation is falling.