Timeliness of Games

Hi all.  Im new to chess.com.  I have a question regarding a subject that I am sure is common to the community.

Is there a maximum number of games that players can have current at any given time?  If not, do you think there should be?

Many players would like to enter into a game that will last only a few hours.  However, it appears that many players are grabbing any game out there and completing them at their leisure. 

How about a 15 minute maximum per move?

A 15 minutes per move game sounds like a disaster to me. The average number of moves per game on this site is 48. Even if the first 10 moves come off pretty quick, you've got typically 38 moves at 30 minutes per move = 19 hours to finish the game. And you wouldn't be able to take a break because if you're opponent moves, you're on a 15 minute clock.  I don't think I could play chess for 19 hours straight.