The barrier of entry for media is very low now. That means a lot of things that wouldn't have gotten made now get made.
What that also means is that there is much more cheap junk pushed out the door. The investment to try again is now much lower than to try to add meaning to so-so film, so you just quickly land it and move on.
There is certainly survivor bias when looking at the quality of older media but at the same time, the incentives to only produce quality media has evaporated.
We're in the stochastic age where all business is run on chance. Don't make 1 good films, make 20 and hope one is good.