First of all, a "healthy Collins" is a semi-mythical creature. Secondly, is it too much to ask not to make a historically bad defense even worse? Towns is in effect a league average player - he's a
great offensive player (but see below) but literally
the worst defender in the league.
Also: in today's league, the job of your bigs is primarily defense. There are no successful teams with all-offense bigs. I bet Jahlil Okafor or Boban Marjanovic could put up KAT numbers if they played the same minutes as him - but nobody will play them those minutes FOR A FUCKING REASON (well, in Boban's case it would probably kill him).
You know the only player that you might successfully pair Towns with? Ben Simmons. He's a fantastic defender and a big guard who can't/won't shoot. Even then I bet it wouldn't work. Towns is a modern day Shareef Abdur-Rahim.