>"Everyone" very much didn't. Most of the people in my life have seen the movies. Relatively few have read the book even now.
Those aren't the people that read fantasy in the first place. If they haven't "read the book even now", it's not like it matters that they seen the movies. For them it could be any other movie in their place, and they would be just as satisfied.
The point was that the people that read fantasy in the first place other than when nudged by movies is a tiny little subset of people.
And the proportion of people who rarely read fantasy who went on to read LOTR multiplied it's total global sales several times over in a few short years after it'd been out for half a century because of those movies.
Those aren't the people that read fantasy in the first place. If they haven't "read the book even now", it's not like it matters that they seen the movies. For them it could be any other movie in their place, and they would be just as satisfied.