You don't haven't to play day in and day out to rank up. When jimmy tweeted that " rank is alive" he meant its based on your activity ( games shown on player channel) and how well you do in those games. Example:
Say you play 5 games getting to rounds 20,25,30,35,40. Add those
and u get 150 . Divide that by the number of games played (5) and u have an average round of 30. That average gets pitted against the total downs of those 5 games. The higher your average round and lower your total downs are the faster you will rank up.
Custom games appear in your player channel. If u don't play and clear out your channel you are resetting the process for you to rank up. So what I mean is if you have a bad string of games played ( custom, solo, and public continute towards ranking up) and you have an average round of 15 it's better to not play for a while and let your channel clear it's self out rather than playing more games with that current average " 15" and spending more time trying to bring up a low number.