How protoss dealt with terran bio before disruptors?

Today even on pro level protoss mostly relies on lucky disruptor hit in mid-late game PvT. I wonder how protoss was able to fight terran before disruptors existed?

Colossus is so expensive, does not deal a lot of damage, and dies very fast to cheap and mass-producing vikings. As for storms, pro terrans are really really good at dodging them, so not much damage either. And that`s assuming that HTs do not get disabled by EMP before the fight, which often happens.