so If I'm playing along side you and I have purchased all the top armor, items and weapons you won't care?
Not at all.
Will you top the board? Sure. We all get the same amount of experience and as long as we extract, its the same.
Do weapons/armor determine if you extract? Probably a good part of it. You can put top armor and weapons in the hands of anyone but if that player has no idea what strategy to use in threatening/perilous because they've always been able to Rambo on routine, it isn't going to matter.
I've seen players who play routine to level 16 then jump in perilous for the first time and try to play the same way they did on easy mode. They get annihilated.
Odds are someone who knows the strategies to play perilous already have some top tier weaponry so it really isn't going to make that much of a difference. I could buy punched by the maker for $$$ or I could use the RNG awarded Griffon I already have and waltz through threatening and come in the top two in perilous 90% of games. Not that much of a difference really.
The difference comes in when I know the DC is jumping at me and I can get away without getting one shot, or when one of the other jumper demons (idr what they're called) is on its way. I'm aware of my surroundings and can adjust to them. Someone who levels in 20 games of routine paying no attention because they barely take damage then jumping into perilous won't know WTF to do and will probably Fade by zone 4.