I think you're somewhat underselling the problem.

Even in Wales, 25% can't. This isn't a figure you can ignore.

And that's a hypothetical, it relies on landlords playing ball etc. then there's the social issues. On the north of England we have lots of terraces built for mill workers, these aren't owned by the richest on society. So then you're in the situation of charging the poorest more for transport. And these are necessarily on towns with good transport links (think 1 bus and hour).

Many of those "can't" won't have cars. 20% of households in Wales have no car.

Now clearly that 25% and 20% won't overlap exactly, but they will overlap a lot

When 80% of cars in the UK are electric and 20% are those households who rely on public streets to store their belongings for 23 hours a day, then sure that will be a problem

Given that there's only about 2 million electric cars in the UK, yet 18 million homes which can charge electric cars, that's a long way off.