TfL Rail (soon to be rebranded as Elizabeth line) have been running the trains for quite a while between Paddington and Reading. The 60+ Oyster card is a London thing and TfL/the Mayor can’t justify extending it beyond London.
As I said, you can buy a ticket from boundary zone 6 to Reading. You can get that at Paddington and you can even use the combination on the fast GWR trains. Freedom Pass holders who can travel all the way to Reading are limited to the slow TfL trains.