That's because chess.com players pool is very large, and most players are recreational players. So if you're a regular player, you end up on the top end of the ratings quickly.
OTB competition is much tougher, so no surprise there is such a rating gap between the two.
Does anyone else think that the tactics trainer ratings we get are EXTREMELY over-rated? It's almost comical. Our true playing strength seems to be several hundred points lower than our tactics trainer rating.
I realize that different ratings are on different scales and aren't meant to be cross-compared, but there must be a correlation. I'm curious to know what's the relationship between tactics ratings and actual playing strength.
Here's my suggestion: could chess.com make a graph with the tactics ratings (y-axis) plotted against the true OTB ratings (x-axis) for everybody? Of course, we could only include people with both an OTB rating and a tactics rating, but there should be enough members to give a statistically sound picture. It doesn't matter if the OTB rating is FIDE or USCF -- they are fairly close for our purposes.