Like if we wanted the best gear, we would have to boss the hardest monsters. If we have to boss the hardest monsters surely, at some point of your hardcore ironman, something bad is going to happen. You're going to misclick an ability, misclick a piece of food, lag out.....anything that can cause 1 even FLUKE death means the end of your hardcore iron man.
I'm not seeing any payoff for that high of a risk-reward. You get a custom title and maybe a high spot on a stupid secondary leaderboard.
It's not really something that can be recognized by all of the Runescape community, at least it doesn't sound like it.