It's not like they LOSE money from unlimited data customers. They might not make as much profit as they'd like, but it's still revenue, so why mess with that revenue and annoy paying customers by cancelling their plans? A number of them won't switch to a new Verizon plan--they'll go elsewhere for at least two years, and some will leave forever.
A few reasons:
1. When the unlimited users are using 20+GB a
month they are using more than ten times the bandwidth of an average person. So easy math- every unlimited user Verizon dumps is ten normal users they can sign up without adding new towers.
2. Verizon has a terrible perspective as a company so I assume they see those users as "stealing" bandwidth from them RIAA-style.
3. Because most of the unlimited LTE abuse comes from tethering, the unlimited customers are driving the unlocking, rooting, and hacking of Verizon phones. Verzon's worse nightmare is a nerd tethering to a laptop that won't pay the fee for the mobile hotspot and so much per gig.
Put them together and honestly I am surprised Verizon kept the unlimited plans around this long. These are the exact kind of customers they would LOVE to dump on T-Mobile, and replace them with thousands of grandmas that use LTE to check a Facebook feed.