Earlier quoted context omitted.
Why can't you buy your own devices? I live in the UK and have always bought my own devices, it often works out at about half the price over the term of the contract.
UK (like most of the world) uses GSM. With GSM your identity is linked to your SIM card. Put your SIM card in another phone, and "you" are still "you" as far as the phone company can tell. Verizon (and most of US) uses a competing "standard" called CDMA, where your identity is coupled to your phone. Which means you have to involve your phone company in order to switch phone.
And that's a pretty good reason not to go for Verizon. It's not that you don't have a choice.
I am with t-mobile ever since I remember, just because I refuse to give my money to AT&T or Verizon (and also to Sprint as they are CDMA).
It's your money, and it's your decision.