I sincerely hope this sends the message that no game should firmly rely on the expectation of an esports competitive scene. It’s a fantastic thing to have happen, and has occurred even for party game Super Smash Bros with no esport support, but it’s not something you can force.
The thing is, it's pretty much Activision Blizzard's fault here. They destroyed the grassroots competitive scene to make way for the Overwatch League, but that took a bit more than a year. They could've found a way to integrate the existing scene instead. And that was just the start of the League. The game itself was mismanaged with the sequel taking way too long and being misunderstood (with good reason).
There were some many mistakes with the Overwatch League, that I don't think we can use it to generalize that much. ESports was a bubble though, no doubt.
OWL biggest mistake, imo, was accepting whatever deal YouTube gave to them. Even if the money allowed for better production value, no esport is gonna take off on YouTube
There were just so, so many mistakes. Avoidable ones too. The pandemic was unavoidable, but the structure of the League made it more difficult to get through.
I don't think it was necessarily a mistake. I regularly watch CSGO/CS2 tournaments on Youtube (as opposed to Twitch) because the viewing experience is just straight up better. Video quality is better, you can rewind back, you can pause and continue where you paused. The only big reason to prefer Twitch over Youtube is the chat, but the majority of time Twitch chat is cancer and I have it off anyway.
No Esports taking off on Youtube isn't the fault of Youtube, it's the fault of viewers who are too ingrained into Twitch.