> There is a lot of consideration in committing that recurring payment for .. indefinite duration.
It's (yet another) negative externality of the Anti-Money Laundering / Know Your Customer mania.
If it turns out that a drug cartel used one of these crowdfunding platforms, the government will kill/bankrupt the platform. Requiring recurring payments is the only reliable way to screen out prepaid gift cards, because prepaid gift card issuers are no longer allowed to process fixed-amount recurring payments.
Any other approach is EXTREMELY labor-intensive and still doesn't work 100% -- for example look at Amazon AWS, which devotes a huge amount of effort to playing this whack-a-mole game and yet still isn't 100% successful. AWS bills aren't the same dollar amount every month so they can't go this route.
Basically AML/KYC is Why We Can't Have Nice Things like micropayments or even one-time minipayments to individuals without something like Paypal where they randomly lock up your money for 180 days while demanding "papers please". AML/KYC simply does not scale down to micropayments or even near them. It's not about the payment processing technology, it's about the legal/regulatory burden.