Why don't major books offer Over Under 2.5 sets?

[Gaze73]

Every single time I expect a 2 set game I bet on the game under and it's always a 2 set game that goes over.

[PharaohUB]

Hmm that's weird, most my books have it. You could always bet the over/under games that usually cashes in same pattern, but get it's not the same.

[HeeeHAWWWW]

Set totals have never really had much demand, for whatever reason. Asians like them though.

[Vyasports]

Because more than 90% of the time under 2.5 sets will be favorite even when both players are 50/50 (except in GS)