I disagree with you here. I live in Poland which has a very popular e-commerce website known as Allegro.pl - it's very similar to Amazon. It has its own version of Prime which is known as Allegro Smart which provides benefits such as free shipping and easy returns. A seller that wants to make their products have Smart badge don't have to use Allegro's own delivery method (Allegro One). The requirements for a Smart badge are as follows:

- have at least 5 positive reviews

- at least 98% rating (if their deliveries are slow, they shouldn't expect a high rating from customers)

- passing Allegro transaction identifier to a delivery service

- they have to provide at least one of the following parcel delivery services as a delivery method: Poczta Polska (which is owned by government), DPD or UPS

Amazon forces third-party sellers to use Fulfilment by Amazon in order to have Prime badge, something that a very similar service doesn't do.