I don't think brakes in sail planes were not thought out, but technology has improved quite a bit since the original status quo. Both disk and drum can absorb the energy, but the disk seems able to keep doing it over and over without causing maintenance issues.

My last glider had a drum. First with a cracked drum and glazed linings and then with an whole new system freshly tuned from Tost. The old system would eventually stop the glider, but wasn't that great. The fresh system was good enough to put the nose on the ground in soft dirt. Not sure how long it would have kept doing that, but a lot of drum problems may well be maintenance issues.

The current glider is heavier and has disk with hydraulic assist. These definitely work better when glazed than the drums work fresh. Fortunately, I've not yet needed to see how much better. I didn't really plan to have disk, but I can see how if one were concerned about really short landings, then these are worth considering. If I had know this when I redid the drum system in the last glider, I would have switched to disk.

In terms of stopping power It's hard to beat a tire running sideways in a low speed, 180 degree ground loop. YMMV depending on the tail boom structure and control inputs to full stop. Still, it beats a collision even if you to have to inspect the wheel and tail structures and pilot's shorts after the manouver.