My home charger was like $500 ($300 with the credit I got from electric company) and install was like 250. No upgrade needed.

I've also owned a house before that had old electricity - knob and tube (this was before I had an electric car) and paid less than 10k to get the entire electricity system upgraded to something modern. I dont think your 5k-10k thing is accurate for the vast majority of houses.

How long ago was that? Things have changed in the economy recently

It gets tricky once the utility company has to hydrovac an upgraded supply line to your house. They've estimated $30-40k for me.