I think in some cases, it's part of the planning permission for Amazon to pay towards public transport to serve the area of the site. Though it doesn't apply to all Amazon locations.

Follingsby Park is just sadly in an awkward location meaning either a service terminating there and returning to Heworth, or buses having to loop back on themselves to carry on to their destination. A way around it is to alternate journeys via Amazon, but again would leave an uneven timetable and even worse longer gaps in certain locations between runs if there was a bus missing.