Low is a subjective term. I played a lot before paragon was added... I have a wife, a house, 2 kids, and a salaried job. When your have responsibilities spending 400 hours on a game (10 fte work weeks) is a lot.
Maybe, your "not playing much" is in comparison to the fact you may not have responsibilities? Or compared to spending all available free time on other games?
You probably play as much if not more than me. You say legendary drop rates are fine, which means you have gotten them to drop on the PTR and have played enough to give a reasonable estimate on their droprate. I have only seen about 2 legendaries drop on the PTR (outside of boss kills like rakanoth) and I have spent a fair number of hours on it.
I have a total of ~200 hours into D3 since release, for what it is worth. And you really have no clue what my responsibilities are, that is the most unsafe thing to mention ever online. I work 2 part time jobs, go to college beyond full time (12 credit hours is full time, I am taking 16), car payments and rather substantial (for me) medical payments. I may not have a wife and kids, but I have plenty of other responsibilities.