That's news to me. I see Mac Minis with external drives plugged-in constantly; I bet those people would appreciate user-servicable storage. I doubt they bought an external drive because they wanted to throw away the whole computer.
External drive is workaround to apple’s pricing scheme, often purchased at same time as computer.
Mac minis have user serviceable storage: https://store.m4-ssd.com/products/third-party-ssd-for-mac-mi...