Protoss player here.

A lot of units are "overpower" but when it comes down to economy you cant fight terran, cuz they dont need as much to pump their CHEAP UNITS.

Dont need to talk about late game or tier 2.

Lets talk 3 rax MM. vs 3 gate Zealot/Sentry/Stalker

25 SCV vs 25 Probe = equal (cost wise)
3-4 supply/pylon=equal
3 rax vs 3 gate = equal
2 tech lab 1 reactor (150 min 100 gas) vs Core = Toss leading 100 gas
Concussive Shell 60 seconds vs Warpgate 140 secs (close to 70 if spend 4 chrono boost) = almost equal

Army (this is where it goes IMBA)
3 marauder 2 marine (400 min 75 gas) vs 2 zealot 1 stalker 1 sentry (375 mineral 150 gas) = equal considering toss was leading 100 gas.

then ask yourself this 3 marauder 2 marine vs 2 zealot 1 stalker 1 sentry OR any combination you want with similar cost.

Can the toss win? with the concussive shells? NO NO NO!

that's not even considering the fact that if terran all in marauder which means lesser scv MORE units.

Is there a way to beat this? NO.

its basic math. 100 min 25 gas unit >>>>>> 125 min 50 gas units or 200 mineral (2 zealot) or 150 mineral (1 zealot 1 sentry)

wow i not even talking about mule and chrono boost.
and i'm talking about marauder not marine...
2talker 1 sentry 1 hit ko marine? wow of course la but marauder?
1 zealot 2 stalker 1 sentry? wow you try vs 3 marauder and see with concussive shell you dead.