HTC needs to remodel their business just like the One series inspired for.
Good theory, terrible practise.

They have to realize they aren't competing with Apple or the other OEMs, but with Samsung.

They should make a unique clean design hardware.
Then really alter Sense so that the customizations to stock Android are for the better (take some cues from MIUI, AOKP, Paranoid etc etc).
Then they should price it aggressively and market the hell out of it.
... this would be them selling at a loss.

But next quarter, market slightly less and increase prices slightly.
They have what it takes to match Samsung, they just need to competent enough to do it.

(PS no locked bootloaders, no carrier bloatware)