I agree with you that better mass transit is needed as much or more than bike infrastructure, but I want to check one of your assumptions.

I bike 9 miles to work every day in 38 minutes, the car trip is 20-25 minutes due to traffic. The key is an e-bike. I've put 3k miles on the bike and at this point it has paid for itself and then some. Cars are expensive to drive, maintain, and purchase. My wife and I share a car and I supplement it with an e-bike. Considering she was considering getting an expensive new car before we started sharing, we've probably saved $40-50k in the last 3 years by removing a car from the equation. (Cost of car, insurance, maintenance, energy use per mile).

E-bikes use such a tiny amount of electricity, I'll probably only use two tanks of gas worth of energy in it's lifetime, maybe less.

Over the course of the next 15-20 years, repeatedly buying and maintaining one less car will likely shave several years off retirement and the biking will keep me healthy in the meantime.

Edit: Like you I overestimated the burden of riding a bike before I tried to make it work. Now that I'm doing it, it's almost entirely a positive outcome.