The room plays a big part - if you play in an empty basement room next to your bicycle - then the sound is very different from the sound of the same amp (or KPA via great speakers) in a recording room.
IMHO depend the "In the room sound" on 3 things:
a) We have to play as loud as we would when we play a real amp - and need some big speakers to move air (not 6" studio monitors or even headphones)
b) Even when we use a real amp/cab - we never hold our head close to the speaker center. So the miking for the "In the room sound" must not be close to the center of the speaker
c) The sound of any real guitar cabinet (next to us) can not be captures by a single SM57 close at the amp. So other or more microphones must be used to get closer to this sound
When I profile any amp I profile in the same room where the amp is - and playback the captured profiles - in this same room - and try to get both sounds as close as possible.
This approche is NOT possible if you put the amp into an isolated amp room and profile in the control room.
It's myth also that this "miked sound" was invented because it sounds this great - a lot of players would love to get their "amp in the room" sound recorded or played via the PA - but this was not possible before the KPA. Or only in the studio via a lot of work - live (via PA) is this sound impossible because with a real amp - we need to close mike or DI the amp or get a total mass.