I can only speak to my own use of cellular data but the point for my family is that there are no options where we live. Out in our rural area, there is no high speed internet via physical connections (DSL, Cable, Fiber, etc) short of paying $30k for Comcast to run a line 1.5 miles to our house. Lots of companies take those government subsidies to build out into rural areas but few actually follow through leaving us with limited options to stay in the current century (or work remotely for those of us who require high speed connections for work).2TB is absolutely ridiculous. All of the combined devices in my place usually only hit around 500-600GB per month on Time Warner. Talk about abuse of the network. It's not even that expensive to just pay an ISP. T-Mobile unlimited is $80/mo for new customers while Time Warner sells a 150mbps plan with no limits for just $50/mo. What's the point?
So we use Verizon Wireless with an old unlimited LTE plan. Works great for us and Verizon has never sent us any letters about usage. Granted we don't pull down 2TB but my family does about 200-300GB/mo with Netflix/Hulu+/HBO. The day Comcast or another provider comes into our area with 25Mbps+ down and 5Mbps+ up, I'll switch in a heartbeat. I'd even pay $100-$150/mo for it... but I won't pay 30k for the hook up.