The good thing about price collusion is that it's hard to coordinate. If even one competitor defects (and they have every advantage to, as they'll win big), then the cartel falls apart.

One of the big rules of commerce is that competing on price is generally a no-no for large markets. Usually, the powers that be would rather compete on a perceived value; that is how “informal price collusion” works.

Price/cost is the last thing you compete on unless you have a wholesale advantage, which nobody in this particular industry does (visa/mastercard set core rates)

Source: I’ve worked with higher ups in numerous commerce operations.

Commerce is actually even worse than many realize. Look up pepsi and walmart as a small example.

sounds like an org prisonner's dilemma

That assumes that

* it instantly brings them a ton of consumers * they have capacity to serve those customers

if they don't competitor can just keep higher price (especially if it is just small middleman fee most people might not care that much about)

And even if both of those are true worst possible case is them expanding to handle influx of customers and then competition following in few months, making their investment moot