[callmeed]

My guess is that it's because payments are much easier thanks to online and developer-friendly merchant systems. PayPal has had IPN for a long time. Then there was BrainTree and open-sourced libraries like ActiveMerchant. This made billing for your own app and some marketplace options easier. We do 3rd party payment aggregation with NextProof (www.nextproof.com) and I still get an email every week from someone who read an HN post I wrote 2+ years ago. But after the financial crisis, most merchant underwriters frowned upon payment aggregation.

Then all the billing/charging services came along. Recurly, Chargify, Spreedly, CheddarGetter, etc. These made billing and charging your own customers easier. They never really handled "products" but I think they paved the way a bit by showing that having easy APIs is important.

Now you have services like Stripe. So, you can do recurring billing and individual charges. You can let your customers setup their own accounts (via Stripe Connect) but still keep the business logic in your app. This also takes care of the disbursements/payout issue and puts the onus of chargebacks on the user. The API is easy. PCI compliance is not as much of a problem. Transaction fees are in line with PayPal (but our BrainTree fees are lower). You can build a tool like this, a marketplace like Etsy, a crowdfunding site, etc. ... If you look through Stripe posts on HN, the biggest gripe is always international payments. I built www.bngal.com because it was easy and fun.

It will be interesting to see what's next ... possibly integration with in-person payment systems (like Square) or maybe cardless payments (linked to bank account?).