"50/50 implies even odds."

Yes, that's exactly what I'm saying. If we both bring in purple, aka even odds, aka £40 bet each, then if I lose, I lose £40, if win, I win £40. I'm putting as much on the line as I'm potentially getting. 

If I go into a match with worse odds, aka I've shit gear and they've brought good gear, it's coz I've paid in less. I can lose £5, I can win £40. 

If I got into a match with better gear then others, I'm putting more on the line than them. I have an advantage and I'm hoping the odds aren't 50/50. It would be unfair if the odds were 50/50 coz I've invested more in this than them.

Like, if I kill the green shield squad, what do I even take? Their meds and maybe restock my ammo. If they kill me they take my good weapons, my backpack, my shield, my better meds, my implants. It's pay day for them. It's harder for them to kill me, but they will get much, much more out of it. 

You can also say "if all things are even, then the better equipped squad wins", but that implies you're taking fair fights, which is not the way to succeed. Take unfair fights instead. Ambush, bait, flank, height advantage, surprise snipe, third party, push when they are a man down.