They try super-hard to do so every time there's a change on the account (probably 90%+ were lost when the "free phone" came with a new contract), and they've raised prices (+$20/line). They also instituted the 200GB (maybe 100GB) limit.

http://www.droid-life.com/2015/10/08/verizons-20-unlimited-p...

https://www.washingtonpost.com/news/the-switch/wp/2017/01/11...

http://www.droid-life.com/2016/07/26/fyi-verizon-unlimited-d...