You can. Buy a Tivo, and you can use it for any operator, and resell it. Just make sure to get lifetime to keep your ROI up. Best buy will give you a gift card for $50. You can get the "low end" model for $150 w/ 4 tuners which currently bests anything TWC or Verizon spit out.
I told my brother to buy the Tivo w/ lifetime and use his home equity loan to pay for it. By my calculations (he has 2 TV) he is saving over $30 a month, and sold off his old Rokus.
And Tivo is far superior to any operator device out there.
If you look in Canada, they mandate operators sell the equipment and my entire family and a vast majority of friends buy the equipment, because it is much cheaper.
Brother still has a Tivo2 in production which is 8 years old...
My sister went the Tivo route with Comcast and has no problems with it. The problem with Verizon is On-Demand is IPTV based and not compatible. You don't escape monthly fees though as they still charge for cable cards.