I don't think having better reads on opponents would make me win 4x as much money. 4 tabling at say 75% of my potential wins more money than sitting at one table and picking up accurate reads on every player.

It also isn't hard to pick up small reads on people when 4 tabling. I'll often note that a person might call the flop with nothing then fold to a 2nd barrel or that they will chase draws endlessly.

If you want to focus on improving your skills and hand reading then I would 1 table but you will make less money.