Verizon makes way more than enough money to pay for any increases in network demand.
Verizon reported earnings for their 3rd quarter on Oct. 19, 2017. Their
net income for the quarter was $3.62
billion.
Their free cash flow from operations totaled $17.2
billion during the first nine months of 2017.
https://www.wsj.com/articles/verizon-continues-to-win-wireless-subscribers-1508417409
Net income means what they get to keep minus cost of goods sold, expenses and taxes for an accounting period.
Free cash flow is the money left over after all capital expenditures.
Capital expenditures is the money spent by a company to acquire or upgrade physical assets such as property, industrial buildings or equipment.
Verizon can afford to include this 4K unlimited streaming feature for free with both of their current unlimited plans and still make a crap ton of money.