> [Can't we just] make democratic decisions about how to allocate healthcare funds?

And then, the rare conditions are starved of funding because everyone votes to throw more money at cancer/something well publicised because they spend a lot of money in marketing.

How does that help the rare sufferers, if their vote is never enough, and their voice drowned out by the megaphones?

I wouldn't be surprised if quite a lot of funding for rare (and not photogenic) stuff came from 'selfish' wealthy individuals with a vested interest.