I think the issue between Glenn and most guitarists is that Glenn lives in a world of (high gain) close mic recording (quantitative), and most guitarists live in a world of how things sound in the room / live (qualitative). Trying to recreate some of these things myself, I've found that both points of view are more or less correct. Eg. when you close mic record high gain, speakers & mics make a big difference, amps may make a difference, and nothing else really makes much of a difference. In the room however, for reasons I have a theory about, I feel (there's the operative word) like I can detect differences all the way down to what pick I'm using!
To the tube guys, I challenge you this. Make a close mic A/B recording USING A REAMP (critical) where you hold literally everything exactly the same except the tubes, and get back to us with the sample. I did this with an amp where I swapped 6L6 running around 36 mA vs a set of EL34 running around 17mA. Should be vastly different, right? Sure "seemed" like it in the room!
To the amp guys, here's a reamp comparo I did with a Mark IVb vs a 6505+. Again, should be vastly different, right? Sure "seemed" like it in the room!
If you want to talk close mic high gain recording, the things that do matter are speakers..
...and mics. Remember- EVERY TONE you know and love from songs you've heard- WERE RECORDED.
To be clear I'm not here to defend Glenn as I think he has been sucked into jerking off for the algorithm because that's his income now. What I'm saying is that the issue here is perspective & perception, and when you align those things I believe it's probable that both sides are correct. So, I'll leave you with this thought. Are you trying to solve the problem, or are you trying to win the argument?