Comment by sersi

For sure, the author simplified things for the article. Anyway, in the case of VHS, they were indeed based on the 35mm scan but then had additional magenta added (as well as pan and scan to change the aspect ratio).

The author is not wrong that oversaturation is a source transfer phenomena (which will always be different unless special care is taken to compare with the source material).

On most TVs that magenta wouldn't have shown as much as the youtube video shows because TVs tended to have weaker magentas. Of course, it's not like TVs were that uniformly calibrated back then and there were variations between TVs. So depending on the TV you had, it might have ended up having too much magenta but that would have usually been with more expensive and more accurate TVs.

TLDR: Transfers are hard, any link in the chain can be not properly calibrated, historically some people in charge of transferring from one source to another compensated for perceived weak links in the chain.