That's a chicken & egg problem though. In fact CI slots used to be more popular but declined as the system was pretty much never used (pay-TV is typically only

That's a chicken & egg problem though. In fact CI slots used to be more popular but declined as the system was pretty much never used (pay-TV is typically only used for high-end services which then provided their own set-top-box offering extra features such as recording or catch-up TV services over the internet). The problem can also be trivially solved by cheap set-top-boxes (during the migration to digital TV, DVB-T tuner set-top-boxes were already inexpensive and technology has advanced even more since then) for the immediate future to avoid forcing people to upgrade their entire TV sets. Key distribution is already a solved problem as well, the UK has a large userbase of smartcard-based prepayment systems such as for electric/gas meters or transport cards (Oyster card) and every tobacco/liquor store has a terminal that can sell or reload these cards. Expanding this system to reload TV cards is just a software update.