Everything at an exchange is "off-chain".

Almost all bitcoin transactions in the future will be done on exchanges, between bank accounts, or through digital warehouses without any bitcoin moving on chain. I'm not holding mine like that but you know most people and companies will, out of fear or because they don't know any other way.

The end game is bitcoin becomes the settlement layer for the world. Transaction costs are going way up in the future, you're not going to want to do on-chain transactions when it costs $1000+ to do so, but if you're settling a billions dollars, that's a tiny price to pay.

The fact is, whether we like it or not, very few individuals (other than those of us here) will hold private keys in 10 years. The transaction costs alone will ensure it.