A cynic could argue that the focus these days is on “keeping...

A cynic could argue that the focus these days is on “keeping very sick people alive” and dependent upon drugs. This gives rise to obscene valuations for drugs that merely prolong life by months, rather than cure.
I would suggest that PYC should enjoy a much greater valuation if it’s intervention stops the progression of RP because, as you say, their quality of life is improved for decades. (Not to mention the reduction of fiscal burden on Govts, caretakers etc.)
But, as we know, one is entitled to one’s own opinion, but not to one’s own facts. The market might take a different view.