It's slower than for houses, but apartment parking can have charging points.
The parking where I live in Copenhagen has two spots with chargers, and they (like all the spots) are reserved for specific cars. I suspect the people paid at least part of the installation cost. They were installed 7-8 years ago. The electricity cost should be very low. This is no different to owning a house.
More recently I've seen commercial low-power (~7kW, standard three-phase supply in Europe) overnight chargers by apartment buildings, in the parking reserved for residents. Presumably people try and get one of these spots often enough, but as demand increases they will need to install more. The electricity cost is probably a bit more, to cover the overheads of the company maintaining the charger. If the spots are a free-for-all, I'd not want to rely on needing one every night, but it could be OK for a car that only needs charging once a week or so.
Also, most of those who already choose to not own a car are already in that 35%, so of "people looking to buy a car" its even more weighted towards that 65% who don't live in an apartment.
No one runs numbers thinking the non-apartment dwelling population is going 100% EV. So 30% EV adoption is pretty mainstream, but not if it's 30% of 65%.
If 50% of non-apartment households got an EV, that would be ~33% of all households with an EV. With your definition of 30% == "pretty mainstream", it is pretty achievable to have EVs be mainstream while excluding every apartment dwelling household.
Roughly 8% of US households have zero cars. What do you imagine the breakdown is between apartment and single-family households? I'd guess probably all dense apartment, the main cohort we're talking about that would lack charging access. So for those actually looking to charge a car, if 50% of single family homes moved to an EV that would in reality be even more than just ~33% of the market, because 8 of the 35% of apartment dwellers weren't shopping for a car to begin with. It is really more like 27% of households want a car and live in an apartment that would be challenging to charge a car in. But hey unless we solve it for 27% of the population it just can't possibly be considered "mainstream".
