Verizon has long-term agreement plans, but in many areas, they also offer month-to-month agreement plans.
In NYC, the only difference between a long-term agreement plan and a month-to-month agreement plan is that you get a 2-year bundle discount instead of a 1-year bundle discount.
Yes, you can choose to sign a contract for fios in order to lock down a lower price and avoid these rate hikes, but they aren't required. You can opt for contract-free fios, but it may cost a little more in the long run.
I myself signed a contract in order to avoid any rate hikes, at least for 2 years.