warlord's bloodlust keystone

is it underrated? Almost %90 of community prefer fervor but isnt surviving better than dealing more damage sometimes?

( btw can someone explain me why people get warlords bloodlust on draven)

I see people playing olaf,aatrox,yasuo with fervor but when I play with bloodlust I just feel stronger.

I find bloodlust 2x better than fervor in mid-late game. I tried it on tryndamere also, well you lose some damage in general but your sustain goes insane.

am I wrong?

If you guys have some time can you really explain me?

I want to give an example on tryndamere.

LETS SAY, you could kill enemy top laner with 5 hits.But you can survive 3 seconds. Without fervor 6 hits. And you are in mid-late game with 4 items on you.

With bloodlust, you could kill him in 6 hits but you can survive 4-5 seconds. so for losing damage equal to 1 hit, you gain more seconds to survive. Am I thinking wrong?

Ofcourse without fervor I dont feel im dealing any damage until mid-late game where bloodlust actually starts being usefull.