While its true that cash tables are not used as much as Zoom, but you need to remember that volume is key and Zoom you do almost x3 the amount of hands in the same amount of time.
Also Zoom tables mitigate people who have App's like HM or PT because in a pool of 300 you will play a single players on average 1 in every 60 hands in 6max so it takes a significant time to build solid data on a player which can be used to exploit them. In a cash table you'll be able gauge the alot more from 60 hands and begin to classify the type of player you are against.
There is still good NLHE cash game action on the sites I play. A lot of the action is definitely fast fold now, but those are generally good games. So while I agree that spins have taken some cash action, I think you can still find plenty of good cash games online.
There are lots of cash tables running on the international pokerstars site 24 hours per day. Maybe not as many as 10-15 years ago, but since you are only allowed to play 4 at a time now, there are still more than enough for anyone to choose between. On small poker sites it can be more of an issue.