We were in Cozumel over the Xmas to New Years Week. Actually flew in on the 25th.
Taxi driver said 12 cruise ships in that day!
I've read that Cozumel is expecting 1.9 MILLION Cruise visiters this year. A new building/plaza area was built right by the pier. Its got all the chain resturants any Good American venturing into foreign lands needs to feel comfortable... TGI Fridays, etc etc.
The old main square was empty at night. We drove by on the way to our dive shop during the day and its jam packed with cruissters.
If it wasn't for the currents, I suspect the reefs would be feeling the pain of all that trash and waste that the ships flush out of thier systems.