Im going to say your initial lack of affinity to TOS is part of it. Another part is you obviously weren't there at the time of the theatrical release. It was 1979 which means:
1. There had been no live action Trek in 10 years
2. There weren't near as many movies released in 79 as there will be in 2024, so the movie going audience didn't have as many options to choose from
3. There were no other Star Trek movies to compare it to. Heck, there weren't that many science fiction movies to compare it to in terms of FX, time of release, etc...
Clearly TMP would not be as successful today as it was in 79