A lot of sailplanes don't have certificated electrical systems. No sailplane has a generator. Transponders require power- something that has to be stored in batteries- which are hit or miss for duration. It's going to ground a lot of sailplanes if they HAVE to carry a transponder as the process to get an electrical system certificated when the original manufacturer/designer no longer exists is not an easy one.
It wouldn't change anything in the club. The guys who has transponders still use them, the guys that don't, well, they don't (all of the club owned airplanes have them). It's not a big deal- make your radio call and look outside for the traffic. They don't want to get hit either so you can guarantee that they'll be up on the freq and say something when you check in.
Yes - I am aware. "My club" was in debate about getting transponders installed, but I have not been active with them as time/money does not permit, so I am out of the loop. Last I do recall was the tow plane would have an assigned squawk and the local controlling agency would get a phone call making them aware of operations. Half the airport is under a Bravo to 4,000, so we have to be cognizant of that being mostly windsock children and having good Summer lift. Maybe the whole process will be delayed till ADS-B comes into full effect, and I think the FAA would know that compliance would be an obvious issue. But the result is the same, for the same reason - its still a game of you can see me, I cannot see you.
I want to continue my zero engine add-on again. Besides the aerobatics I have done, that was the most fun I have had flying something. I especially enjoyed riding a thermal at the edge of a stall, feeling and controlling the glider through that region. Lots of fun.