Because that's 'never' happened before.
Ok ok.
I should have said "more users".
I've certainly done it. Back in 2010-2011 I chopped so much crap out of my Silverstone RV03 case to fit the "biggest AIO ever made" at the time, a 180mm CoolIT unit from MainGear in there.
Before it just didn't fit:
So I made a plan:
And after cutting away a big part of that motherboard tray (along the red lines, can't remember what the blue lines were for)
It worked!
This build totally throws off perspective. It looks like a Mini-ITX case, but it is actually a mid tower. Those fans are 180mm, and the two video cards were Asus's monstrous triple slot DirecCUII Radeon HD6970's.
I had seen this 180mm radiator on MainGears website, so I cold called them and asked if they would just sell the cooler without the prebuilt system it was supposed to come in. I didn't expect it to work, but to my surprise they agreed! (And later changed their minds and wouldn't sell it to anyone else.)
The biggest AIO you could otherwise get at the time was a 240 (2x120mm) unit like the Corsair H100, but if you do the math, the radiator volume on a single 180mm radiator is actually larger than two 120mm's.
That thi g gave me record overclocns out of my Phenom II x6 1090T (4.2Ghz if memory serves?).
This was my "get ready for bulldozer" build. I had bought an FX990 motherboard and was just waiting for bulldozer to drop one in, and when it launched and sucked I abandoned that plan and got an x79 and hexacore i7-3930k instead.
The cooler was able to allow that CPU to run rock solid at 4.8Ghz, and at 4.8Ghz there was nothing that could touch that 3930k for years. Ivy Bridge and Haswell models had better IPC, but couldn't clock as high as memory serves.
That's probably why that CPU lasted me for 8 years, the longest of any in my main machine. I still have it in my testbench.
All of that said, we on here are outliers. We have always hacked and modded things. What I should have said is that now more people likely will