I just had a top lane rengar freeze lane/last hit the ENTIRE game

He lost the top tower inhibitor, he just last hit cs while their top lane was around the map pushing objectives with the team.

He kept saying he was building a massive wave to waste their top laner's TP, but top tower never went down for the whole 28 minutes of the game, and the TP he 'wasted' from their top laner was inconsequential to the rest of the map. Meanwhile his lane was the only lane to lose inhibitor. He just wanted to CS. By the time he did any fighting, the results were he'd engage and die every time, without even being able to kill his target.

We only won the game because the rest of the team knew to follow up on his inting strategy.

But it left me wondering, is that a legitimate strategy? Even if he had lost a lot of CS in the laning phase, should he have just sat in top lane to last hit for 20+ minutes?

He didn't even build tiamat.