When Cox is All Digital Why will the signal not be compatible with my HDTV & Smart TV's built in digital tuners?

I got rid of digital cable years ago in favor of basic cable combined with many internet streaming services, now I am being told that I MUST acquire a small digital tuner or I will no longer be able to access basic cable.

My TVs can decode digital signals so I am asking why when Cox is all digital your system will not be compatible with my TV's built in digital decoders unless I rent and utilize one of your cable boxes.  Your mandate to use these boxes or no longer have basic cable may force me and others to simply no longer subscribe to your cable TV services.

I have been a customer for eleven (11) years and I find this requirement quite insulting.  To put it simply I do not want any cable boxes in my home, even if I was PAID to do so.   And again, I would like specifics on why this new all digital network will not be compatible with my many Smart and HDTVs without me being forced to go back and use the antiquated tuner box & remote system.