I've had some passing involvement with bike advocacy and have been a bike commuter in Los Angeles for the past six years. My impression is that in the early 2000s, there was a flowering of bike advocacy and infrastructure.
But now we've reached the point of resistance where other transport modes are pushing back against any more consideration for bikes. In short, cycling is now big enough to matter but not big enough to win.
I've often wondered if there was an approach other than the incrementalist, go-along-get-along approach that most bike advocacy has taken. The electric scooter startups have changed the transport landscape more quickly than anything else I've seen.