...They claim that Betamax was technically superior to VHS, but ultimately lost because of more aggressive marketing by the VHS companies. This is a myth. An Urban Legend.
Firstly, in terms of the image quality, when these formats were viewed on the average TV that existed at the time, the average person could not see the difference between VHS and Betamax.
The real problem for Betamax was that its cassettes could hold only 1 hour, not enough for a movie. When JVC produced VHS in 1976, its bigger cassettes could hold 2 hours, and this advantage of VHS was crucial in the demise of Betamax. Betamax tried to catch up, but at the same time VHS also extended, and VHS always had longer recording times. VHS won because it was better overall. Anyone that claims that Betamax was a victim of marketing apparently has not researched the issue.
There is also a related Urban Legend which claims that Betamax is what the professionals and TV/broadcasting industry use/used (this legend is used to demonstrate that Betamax is superior). You need only research this claim to discover that it is a blatantly false myth. BetaCAM is what the professionals use. Do not confuse Betacam with Betamax because they are quite different formats. The broadcasting industry would never use Betamax because the quality is too low.
Part of the confusion arises from the fact that Betacam tapes are identical in size to Betamax tapes and can be used in Betamax machines, but at this point that the similarity ends. Betacam is a high quality format based apon the component video standard, unlike Betamax. Betacam was launched by Sony in 1982, and is a successful format.