With the amount of companies requiring you to fill out applications online, emails being the main method of communication before a phone interview, and the amount of people doing virtual interviews; I would say it absolutely is a necessity to not just fitting into a modern society, but being a part of one.

It’s not always a necessity, but the opportunity cost of not having Internet can prevent you from meeting other necessities. For example, a lot of jobs require Internet to apply. Not getting a better job might mean you can’t afford food or housing.