It only takes a team 2-10secs to drop one person without getting healed.

I would disagree that this is the norm.
Honestly if you have to seriously buy a specific materia and stack it just for sleep, it means Sleep is over powered.

You do not. I mentioned several mitagations and this was only 1 of them. I purchase stun resist not sleep resist items even though I have the same chance at being slept by a blm or whm that you do.