Ebike subsidies take no time. Increaseing bus frequencies is a bit faster (depending on local job markets). Painting bike gutters is pretty fast. Putting some traffic cones for modal filters is pretty fast.
It’s true that this change will be tough for poor people who bought cars in the short term. But it’s good for poor people who didn’t buy cars in the short term (which is a lot of people with the most need). And good for all poor people in the long term.
If you want to help poor people, subsidizing an antisocial form of transportation that some poor people use is not a good choice.