If you want to get even more in-depth, then you can look at the cut off point for the average PP daily needed to clear the 3mil quota for union events and see how many people even reached it. The score showing in the ranking thread shows the most PP one gained in a single day. Assuming around 375k PP gain is the average per day required for a 8 day event (the last wind union event), the cut off point is around the 2500th-ish ranked player. The other 7500ish players failed to get enough to meet the daily amount and since the score is based on the most gain in a single day, they didn't get anymore for the other days thus not even completing the solo 3m. There are a lot of other variables but if that many people aren't completing their union event, then there's likely many that aren't completing raid events either.
And a small extra tidbit, most of the scores provided by users here, in comparison to the participant count, is that many got into the 1st~1000th rank despite the participants count being around 10k. While its still a wide range, it's still high up there as a whole. So it's probably not the best to use users here as the basis for setting the standard for what most players can or will achieve when everyone is as strong as they are.