SEPTA was the last major system to upgrade fare collection and it looks like they plan to start over.
https://www.inquirer.com/transportation/septa-key-ticket-system-replacement-coming-20230419.html
https://www.phillyvoice.com/septa-key-new-fare-payment-system-smartphone-apple-google-pay/
https://6abc.com/septa-mobile-ticketing-program-key-cards-transit-system-philadelphia/13161000/
https://www.inquirer.com/transportation/septa-key-ticket-system-replacement-coming-20230419.html
https://www.phillyvoice.com/septa-key-new-fare-payment-system-smartphone-apple-google-pay/
https://6abc.com/septa-mobile-ticketing-program-key-cards-transit-system-philadelphia/13161000/