I am at least aware of the diagonal recording on VHS tapes, that is why I assumed it might be hard do build a generic reader as you could not necessarily take advantage of the geometry or the speed of the tape or things like that. There is probably a good reason for the complexity inside an old VHS recorder.
Other tidbits I recall from what my Dad told me years ago. He repaired VCRs for a while.
The beta machines would phase shift the signal 180˚ every other frame when writing, and they use that for noise cancellation. VHS did four frames at 90˚ each, because of patents.
The read heads were on a spinning drum. Beta machines had an L loading system that would grab the tape and wrap it almost all the way around the drum with the read heads, exposing more tape at once to the reading mechanism. VHS had an M loading system that grabbed the tape on either side and pulled it up, covering maybe half of the drum, because of patents.
And supposedly VHS won out because Sony was begging a lot of money for patent licensing. But tape capacity was probably a factor, too.
