Hmm, would it be easier to imagine PayPal or Stripe requiring a lot of services? Given its volume of payments, Uber has basically had to re-implement PayPal internally, custom-tailored to its own flow. Companies at this size/scale basically contain multiple whole companies within them. Think of like all the SAAS services that your company relies on, and then imagine that your company now owns all of them and all the services that come with them.
Uber uses Stripe and PayPal to process payments. They don’t need to reimplement either, and doing so would be a bit of a waste.
It’s worth pointing out that not all of the 2200 services may be user-facing. Some may be internal, such as admin tooling or CI services. That said, 2200 seems like a lot!
Sorry, I think you are a bit mistaken about how payment platforms work. Stripe and PayPal provide an interface to a country's banks. In exchange for abstracting away the underlying bank infrastructure, you pay them a fee for every transaction. Stripe and PayPal support a limited number of countries and a subset of the bank's functionality. So if you want to interact with any new countries or access any non-supported financial instruments, you'll have to directly integrate with the banks and implement those yourselves. To give you a sense of scale, Uber's payments volume is like 10% of Stripe's.
