PC clones probably didn’t bother with it due to a combination of ROM BASIC being copyrighted, DOS software not needing it, and GW-BASIC being available so peopl

PC clones probably didn’t bother with it due to a combination of ROM BASIC being copyrighted, DOS software not needing it, and GW-BASIC being available so people could run BASIC programs from DOS. Note that IBM included ROM BASIC on their PCs up until at least the early 90s.