Once again I'm talking about commercial/home use.
1975 Betamax had a 1 hour record time... nobody (referring to home movie renters) cared about which format would win because nobody rented or bought movies to watch at home because there were none available.
So I guess you're right, because in 1975 Betamax owned 100% of the market because VHS did not come out until 1976. From 1976 -79 they were too expensive for home use, and movie rentals had not saturated the home market yet.
In the case of home use, I'll defer to Wikpedia again.
"Betamax held an early lead in the format war, offering some technical advantages. By 1980, VHS was gaining marketshare due to its longer tape time (3 hours maximum, compared to just 1 hour for Betamax in USA) and JVC's less strict licensing program."
"By 1980, out of an estimated 100,000 homes with VCRs, 70% were rented, and the presence of two competing formats meant that renting was an even more attractive choice, since a small fortune (about £2000 or $2600 in today's prices) could be spent on a system which may become obsolete. "
In 1980 Betamax tapes could only run 1 hour in the U.S. and people wanted to start a library of movies, then the war was over before a shot was even fired. Nobody questions the superior video quality of Beta tapes. I believe that people who wanted a superior version of a movie for library or archival purposes, and those who had spent a ton of money on Beta players, kept Beta around longer than its commercial success warranted.