Bike commuting growth has stopped/reversed in most places in the US in the last couple of years: https://usa.streetsblog.org/2017/09/14/bike-commuting-growth...

My worry is that there actually aren't enough people to use the bike infra to justify continued/increasing costs--or at least makes it easy to argue against. For example, there is a bike path next to a new light rail line in West LA (expo line for the curious). I used it to commute for ~1 year and the traffic I observed on it was very minimal considering the cost it must have taken to put in and maintain (lights at night too).

Yeah there are a couple bike hotspots like Portland and Minneapolis (maybe DC?) but outside that, the demand is minimal unfortunately.