I decided to write a long reply on the 1-1-1 since u seem to have a wrong idea of the 1-1-1 thus claiming it is usable in TvZ etc...
First of all, the definition is 1-1-1 is not the general 1rax1fact1starport build... Building 1 rax, 1 fact and 1 starport doesnt make that build 1-1-1... The 1-1-1 build is a well known TvP build and is considered the most abusive overpowered build for tat matchup which even the best terran in the world IM.Mvp agreed upon (look up gisado's writeup on TL)... The core unit in the build is marines, tank (with siege), raven (for PDD and detection) and banshee (with or without cloak)... It is a timing attack which hits at 9minute Why is it abusive and overpowered?
1. Scouting
Scouting the 1-1-1 as a protoss is not easy as the terran would be walling off and the early scouting from ur probe doesnt confirm it... The only time you can really confirm it is the 1-1-1 is when u have an observer out and at his base which would take some time which would lead u to a build disadvantage (see section 2)... One may ask why not u jz poke up his ramp wit stalkers as protoss has been doing? If the terran know what he is doing, he would only have marines and this could mean anything - it cant be 1-1-1, it can be bio with him just hiding his marauder behind, tanks etc... thus protoss keep guessing
2. Build advantage
Basically to handle the 1-1-1, the protoss would need to fast expand as if the protoss stay on 1 base his economy would be behind cause of mules to fund more marines thus bigger army (full 1 base saturation tat is) and if he expand late the expansion doesnt pay for itself... besides for the terran to 1-1-1, he need to be defensive for the tech so u can expand earlier... only problem was when the terran fake 1-1-1 (which is very normal in korean play) and bio builds/ marine tank builds will totally roll over any protoss fast expand... another option would be the stargate route allowing the protoss to scout with and delay the 1-1-1 timing but the build auto loose to bio builds and also the terran can jz go tank marine (puma vs mc in metalopolis)... basically the build which beat 1-1-1 loose to any other terran build...
3. Flexibility
i've talked about how this build beat most protoss build... the reason for this is the flexibility of the build... 1 bunker up the ramp with 2 depot walling it and repairing scvs can hold off 4 gate (especially when ur siege tech is getting ready)... protoss skip robo (templar route or anything) u can jz get banshee cloak and roll over him... that banshee allow u to scout the protoss as well btw... protoss got for stargate all-in (3 gate VR)? getting 1 viking to deny the vision from VR and that allin ended... DT? you got ravens... if u optimize the build well with decent scouting skill, u can react anyhting the protoss can throw at you...
4. Lack of protoss AOE b4 T3
As mentioned before, this is a timing attack which hit the protoss at 9minute... and being on 1 base vs 1 base with mules for equal saturation, the terran would have a bigger army where the extra minerals can be spent on marines... marines are the main DPSers for the 1-1-1... before protoss gets their AOE in T3, protoss rely on forcefields to split the mariens reducing their dps for gateway units to hold off marines... this is negated by the 12 range of siege tanks where the lower dps of gateway units cant kill the split marines fast enuff before being shelled... the same group of marines will of course protect the tanks from immortals... immortals will fire their shot off but nt before dying to marines... basically protoss do not have any answer in handling high marine count (and marines scale very well in numbers)... stalkers are unable to kite without getting shelled by tanks... u need robo for obs thus delaying ur templar tech (charge, storm etc)... the quick 9 minute timing attack ensure that protoss wont be able to get colosus with lance up in time and range 6 colossus is bad vs range 12 tanks and marine support... if u rush for 2 colossus with lance (possible if u cut every possible corners and hope the terran doesnt attack u with bio etc), u still lack support for ur colossus which is bad...
5. ALL-IN BITBYBIT
All of the above is not much of an issue for the 1-1-1... the biggest issue is the allin for terran... 1-1-1 bring around 10-16 scvs to battle wit the army... all of the terran units are range and the scvs will create a nice buffer for the units as they kill the protoss army... they could even bunker crawl and contain the protoss... and funniest part is that mules negate this allin by a lot... if protoss hold off the first push (which he need to suffer damage), the terran could rely on mules and ready for the 2nd attack which is much more devastating than the first (2nd 1-1-1 attack is harder to hold than the first, just tat most people die in the first attack)... look at MC vs Puma agian... MC hold off the first 1-1-1 allin by puma and have a 30 supply lead with all 3 immortals alive... the 2nd allin by puma still kills MC lol... and when the terran main is mined out, he could float his CC to his natural and keep the tempo going while the protoss need to expand when he is mined out... it is a high tempo build which keep the protoss on his toe and that 400 minerals invested on nexus could haunt u...
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The reason above are why 1-1-1 is considered one of the most overpowered TvP build and is hated by almsot every1... everytime a terran does it in a major tournament, u can see TL rages over it... Any1 who follow GSL since season 1 would remember BitByBit.prime.WE which is i think the most hated player in sc2 still atm lol... he is a terran which allins every game with scvs and likewise this build is an allin build... Puma from a fan hero became one of the most hated terran for spamming 1-1-1 vs every protoss and then losing to other players when he cant 1-1-1...
mass chargelot, immortals and a few HT with timing atk can kill this built to be honest. the most important thing is whr ur deathball army is position. it does have a weakness especially when terran mass unit is otw to your natural expansion and the tanks unsiege... at that point of time the odds will be much even, if you let them set up a camping site in front of your natural then its 60-70% chances gg already. i would suggest to counter this built is to rally all your troop to d middle of the map and gain controlof xel naga tower....