I consider UFC 1 to be the early days of MMA, because it was the first freestyle fighting competition with very minimal rules to simulate a real fight.
Pancrase was not truly MMA, because:
- No elbows to the head (neither while standing nor on the ground).
- No closed-fist strikes to the head (neither while standing nor on the ground).
- No knees to the head on the ground.
- No kicks/stomps to the head on the ground.
Shooto was a little more like MMA than Pancrase in that fist strikes were allowed, but its rule sets were still very restricted. For example, elbows weren't allowed. Ground and pound wasn't allowed. Also, fighters on the ground would get stood up after a short period.
While it may have been true that the Gracie used the UFC was a marketing platform for BJJ, the martial art itself was legit and proven to be one of the 3 most important bases of MMA at the top level of competition.