Maybe so but the long term effects of breaking are well known. It doesn't necessarily take extreme breaking just long term abuse to cause severe long term problems.

Gotta admit, I am confused by your posts and "concerns". I'm not sure where you've been hanging around or what you have seen. I have been in the martial arts world for many years, and yet truthfully, I've not seen what you are talking about.

Most schools that I know of only do breaking for testings or demonstrations. That means they might break boards a couple times a year... at best. So how is this "long term abuse"? Long term abuse is something that is done repetitively, over and over and over again, over the course of years.
Student's generally don't practice for their board breaks with boards, they do so with pads. The way you are making it sound, board breaking takes place as a regular part of classes and training. That is simply not the case.
The students you have seen with "curled up and deformed hands"... well I'm not sure if this is an exaggeration, or perhaps you've run into someone who was abusing a concrete block and didn't quite no what they were doing. I think what you've seen is the "exception," not the "norm".
I just have not seen this, nor do I see it as any sort of issue.