I can see what your saying, but the same could be said of many cars and teams over the years, its not often the underdog gets the win when up against the might of a works run team.
The program was always stated as a 3 year run, never more and at least they saw it thru where others have gave up mid program and walked away.
I do like the way they milk the win, the LM winning speed 8 (*or at least one of them) is at almost every motorsport event. Pretty sure it would turn up at a local fete if asked.
Given the amount of GT3 cars being offered, it would make sense to give them a class at Le Mans. With GT1 fading away and rulled out of LM (again), surley it would make sense to ditch the current GT1's, exisiting GT2 would become GT1 and GT3 become GT2 etc.
I do wonder if mercedes would let the GT3 run at Le Mans though. Not their favorite place I think.