Being rural, a few miles out of town, I pay $80 per month for unlimited 3mbps down and 0.5mbps up. I looked at a few cellular providers for data, but since they all charge for a few gigabytes per month, it's not a workable solution. Streaming video uses 100GB or more per month (not even thinking about 4k, as that's not even possible on my internet). Until the cellular carriers stop charging $10-$30 per month for each 5GB block of data, they are just not an option for watching video for many people.
I understand 5G is supposed to bring down the cost of data, but do you really think AT&T or Verizon will pass those savings on to you. Yeah right.
For mmWave to be useful it has to work inside. How many people stand around outside all day watching videos on their phone out in the sun? Exactly. People need their phones to work inside buildings, often times large buildings. Using mmWave means all the malls will have to install DAS systems to provide mmWave to shoppers inside the mall. Grocery stores will have to install DAS systems to provide mmWave to shoppers inside. All the employers will need to install...um, no, they won't, you just don't get any cell service while at work, that works for them.