No, not true. IIRC, Cassettes were 1/8” wide, while 8 tracks were 1/4”. 8 tracks had 4 stereo channels (8 mono tracks) recorded across the width, while cassettes only had 2 stereo channels (4 mono tracks). So in width they were about even.
But cassettes ran at half the liner speed (1.875 ips compared to 3.75 ips? I’m not sure anymore). So cassettes actually had less area to store the same music.
Largely because of the higher tape speed, 8 tracks (in their heyday) had better frequency response than cassettes, and particularly better high frequency response.
8 Track’s (and 4 track’s before them) major problems came from their physical setup. A never ending loop that spooled out from the center, and wrapped back around the outside. To make this work, the tape had to constantly slide over itself, with each layer of the tape rubbing against the layers both under it and on top of it. Inevitably, the tape pack would “tighten up”, and this had several bad effects. More flutter, more abrasion of the tape magnetic emulsion, and eventually, the tape pack would tighten so much the tape was trapped in the center, and wouldn’t spool out at all, thus making the tape unplayable. Most folks threw them away at this point, but many of us opened them up, pulled out a few loops of tape to loosen the pack back up, cut & spliced the tape to remove the (now extra) twists, and put them back in service.
Also because of the way the tape was looped, you couldn’t rewind, you could only run the tape forward. And high speed fast-forward tended to tighten the tapes even faster then normal, so a fast-forward speed was usually only a couple of times faster then normal play.
Advances in recording/playback head technology and tape emulsions is what made the cassette a viable music recording medium, where it had previously been only good for voice. Once the sound quality got better, it’s smaller size and other physical advantages killed the 8 track.
But originally, 8 tracks had better sound, by far.
Ugly