A big driver of cassettes then was the write ability, unlike 8 tracks. You could borrow your friend's new vinyl album, pop in a new cassette tape on your hi-fi, and record a copy of the album to the tape. Of course the Walkman then made listening to your new album fully portable.

They did. However vinyl was considered better than 8 track. Cassette was a lot more portable than 8 track, and so where portability mattered it won. Elsewhere vinyl was considered better than 8 track and so it won (a few years latter CDs came and won).

Those who really cared about sound quality had reel to reel tape, but that was very rare. Almost no albums were ever released on reel to reel. You typically bought the vinyl and copied it to your own reels thus ensuring there were no scratches.

No one used 8-track for the quality. It was portable, and it would play continuously (it looped), great for sitting with your honey in a secluded area. And the physical quality of 8-tracks weren’t great. Based on the number of 8-track cartridges I saw on the side of the road while out running, the tape would apparently come loose from the cartridge and render it unusable.

By 1980, 8-tracks were relics being displaced by cassette.