He is very clear. It needs to be at the protocol level.

Why not have privacy on the base layer?

Cause someone could sneak in an inflation bug?

Ship has sailed to be making sweeping changes to the base layer. People are storing their life savings in this now. L2 of gfy. Satoshi surely considered this already and decided the tradeoffs weren't worth it.

Bitcoin has a 15 year record of running as it is. You change the code this much, you start over from zero.

Because you can trustlessly atomic swap for Monero and back. Get off your maxi horse and use Monero if you need base layer privacy. Nobody is saying. Sell all your Bitcoin for Monero. Reasonable people say. Sell 1% and hedge your privacy risk and have fungible money ready to spend.