Originally posted by SPL

First of all, they record and mix their albums in world class studios, which means exceptionally good acoustics and control of sound. They most likely use SSL consoles to do their tracking and mixing, which are GREAT sounding consoles. They use the best A/D converters out there to get their stuff into Pro-Tools for editing. They probably use all kinds of nice outboard gear during tracking and mixing, mostly EQ's and compressors... I'm sure they use a bunch of plug-ins on top of that.
I think Brad from LP uses Mesa Boogie Dual Rectifiers for amps together with PRS guitars plus probably some Seymour Duncan pickups.
In order to get that big stereo guitar sound like LP you need layers and layers of different takes spread over the stereo image, preferable all with a relatively different sound to give them more seperation and enhance the big sound. Plus, the guitar and bass work together on that sounds, most people don't seem to be able to make that distinction.

Acoustics are only important when mixing as electric guitars are recorded using line input and not miced up I would presume.
SSL is a good console I agree, but you can get a channel strip class A pre-amp for next to nothing these days. You get soundcards with 24 bit/96 khz, so I don't think the difference is that big.
EQ, compressor, yeah it makes a difference again, but still minor.
Amp, guitar, pickup, still small but noticeable difference.

The biggest difference I think is in your last point, layers recorded with different tones, maybe some of the layers slightly delayed to give a fuller sound.Different amount of reverb, EQ etc.
But I suppose if "I" only get 95% of the sound in each phase, then I'll in up with 75%-80% of the sound, by losing 5 % in each phase.
Yes, I have noticed the bassline is usually the same as the guitar.
Hmmm.... it ain't easy.