Some things are easier to change than others - and the really hard things often don't require money, but a change in people!
Edit: Sorry for the shitty OP, I should have known better than to post in a hurry.
It reads as if the population is primarily responsible for combating the climate crisis, while industry and government are off the hook because money has little effect.
What I actually meant to express was that technological adjustments that only cost money are easier to implement than changes to people's habits. Perhaps this is a naive idea because it assumes that there is the political will to make these investments and that the industry is forced to cooperate accordingly. Addressing the climate crisis requires many changes, and economic profitability must be secondary. But achieving this is perhaps one of the most difficult adjustments society requires.
I don't think you'll find anyone who suggests that bikes as a single mode of transportation is the solution.
No single mode of transportation is the solution. The solution isn't "subways". The solution isn't "busses". The solution isn't "trams". Or "cars".
Instead, in cities, the solution is a mix of modes. Sometimes that's using one mode locally and a different mode to get across the city. Sometimes that's multimodal trips - taking a bike to the train then biking the rest of the way, for example.
Bikes are particularly good at solving the "last mile problem", which public transit is pretty lousy at solving. That's why, if you go to train stations in the Netherlands they have bike garages. Because trains and bikes are better than trains without bikes and bikes without trains.
And again, bikes won't solve the last km problem, for the reasons I gave already.