I wonder why PC floppies didnt switch to ZBR https://en.wikipedia.org/wiki/Zone_bit_recording https://en.wikipedia.org/wiki/Zone_bit_recording at some point to

I wonder why PC floppies didnt switch to ZBR https://en.wikipedia.org/wiki/Zone_bit_recording https://en.wikipedia.org/wiki/Zone_bit_recording at some point to beef up storage capacity. Chuck Peddle of 6502 fame did a PC in the eighties called Victor 9000 https://en.wikipedia.org/wiki/Sirius_Systems_Technology#Victor_9000_/_Sirius_1 https://en.wikipedia.org/wiki/Sirius_Systems_Technology#Vict... where he implemented special software driven (6502 controller just like in Commodore drives) ZCLV/GCR floppy drives. 1.2 MB using ordinary 5.25 DSDD disks (500/360 KB capacity in PC). 100% capacity gain from switching to 80 tracks, another 50% on top of that due to ZCLV/GCR. Standard PC 1440KB 3.5 inch HD floppy using same strategy would start at 2160KB. There is this great "Discovering Hard Disk Physical Geometry through Microbenchmarking" blog post by Henry Wong visualizing whats going on on the platters https://blog.stuffedcow.net/2019/09/hard-disk-geometry-microbenchmarking/ https://blog.stuffedcow.net/2019/09/hard-disk-geometry-micro... Whats crazy to me is learning early HDDs didnt use ZBR either, manufacturers were leaving 50% capacity gain on the floor. 1989 Seagate ST157a is comparable to HD floppy, denser tracks at 650 vs 135 tpi, but almost two times lower Bit density :o 10000 vs 17434 bpi. ST157a could lose one platter, or gain half capacity 40->60MB by going with a little bit more complicated ZBR controller (switching bitrate per track).