Microphone pattern (omni, 8, cardioid, hyper cardioid) and distance will affect how much influence the room has.
Decibel output of the amp in relation to the distance also greatly impacts what the microphone will receive regarding room.
A Marshall on 10 will overpower sound coming from the room if it is close mic'ed, but in a small room the reflections are quick and powerful.
As previously stated, ambient mic'ing picks up more of the room, but the profiling homogenizes the sound.
Profiles are 2 dimensional until they are played through a speaker, as an amplifier is until it hits the speaker.
The room makes the third dimension.
At least those are my opinions.