The joys of single supplier most likely. Probably contracted to provide 1 mil a year or something then if tourism greater than that have the "disposable" ones... doesn't need to be any hardware difference though a simple time limited cards get activated with expiration date and server auto permanent inactivates them.

Could be because of some payment regulation. IIUC prepaid payment method in Japan has to maintain a large sum of deposit to cover cost of refunds in case of insolvency situation. Balances on expired cards probably aren't used for that deposit calculation.

Also IIRC, relationship between Sony and JRE had soured few years ago and the fab in Japan that manufactured Suica cards was shut down. The contract went to Panasonic, but looks like Panasonic then sold off the smartcard unit to Nuvoton, and likely some security/nationalistic issues around that was the cause of the card supply issue.

There are really subtle cues to tell the model number(smartcards have model numbers!) and manufacturer of cards, most simply in tiny dent created by the cavity to hold the chip. Sony ones were circular and current cards are racetrack shaped.