I mean, in 1978 Tandy used standard drives and a disk controller IC, and still managed to sell a whole 16K TRS-80 system with disk drive for the same price (TRS-80 Level II 16K + Expansion Interface + disk drive = $1786 [0]) as Apple (Apple II + Disk II + drive = $1790 [1]). Plus, the TRS-80 came with a video monitor wheras Apple did not. But the Disk II could hold more data per disk, and I'm sure Apple's margins were better.

0 - https://ia803203.us.archive.org/9/items/Radio_Shack_TRS-80_S...

1 - http://www.apple-iigs.info/doc/fichiers/Apple%20Price%20List...