The median home age ranges from 26 to 63 depending on state, and 100 amp service was common into the 90s. 100A service is probably more common than you think, I'd bet we teeter around them being equally common.

My home still has 100 amp service (as does almost the whole city, most of it is a historic district), but it was built in 1910 so that's not shocking.

> A electrician can plop in a electric car charger for instance, that is a 40-50 amp circuit.

Oh yeah, I was mostly talking about having to upgrade the service to the house from the pole. A new circuit with a single outlet isn't horribly expensive, but needing to upgrade service is pretty rough.

Newer houses yes probably have the overhead. We put in a charger for my wife (because she drives 100 miles a day we needed a pretty beefy level 2) and had to replace our whole panel because 1) we had 125A so failed the load calc and 2) we had the infamous Zinsco panels and the electricians refused to squeeze one in even if we did pass the load calculations. Luckily we had a basement so they only had to extend the circuits a little instead of rerunning them all over the house.