I agree, but also CP/M to DOS wasn’t superficial. When Paterson did the Z80 port of MS-DOS by running it through an assembly language translator he’d written for the task, the resulting MSX-DOS could run quite a bit of CP/M software without issue. The only major problem was MSX-DOS disk formats using Microsoft’s FAT filesystem. This isn’t unusual though since many CP/M machines had incompatible disk formats anyway.