I think some of the general problem with the HEMA community is that they're constantly trying to reinvent the wheel and seem to be independently discovering martial arts apart from already established martial arts.
A while ago it was making the rounds that the power of a sword swing comes from weight-transfer in the hips... you don't say? This has been a known fact forever in every other martial art that power generation comes from body weight transfer, not your arm... But it seemed to be touted as a revelation for the HEMA community in some circles.
Protective gear is just another symptom. Look at every other competitive martial art. They all wear minimal protective gear, and the ability to get hurt is always present and part of the sport. Boxers and MMA practioners come to mind. If you can't get hurt, you will never learn to defend yourself. Now, of course a newcomer should wear more gear as they learn control etc, as they do in other martial arts, but at the top tier, competitions generally occur with minimal gear so as not to get in the way of technique.
The thing with gear that sets HEMA apart is a steel sword can do a lot of damage, (but so can a fist or knee on the right person), but let's just assume that the sword in general has a greater potential for damage. If we accept that as true, then it would follow that perhaps some more protective gear would be required to prevent grievous injury. It's a hard question... but I firmly believe that at the top tier of any competitive martial art, technique reigns supreme and protective gear will always hinder at that level of play. I think that's obvious to other martial arts, but again, it's only now making headway in the HEMA community.