Internet is not free. You may be finding it free of charge to you, but it’s not free. It’s also spotty as far as availability, even in cities. Being unable to call or receive calls because you’re not in a free wifi hotspot is not practical for most. And, there are some things that cannot be migrated to a web page, PDF, etc., not at the present time and not in the foreseeable future.
So, if you’re able to make do with VOIP, Skype or whatever to cover your need for voice communications, great, good for you. It’s by no means applicable to even a majority though, let alone everybody.
I was assuming you had already paid for Internet, because how can you live without it? Cell phones, not so much.
I use a VOIP phone, haven’t had a land line for years, if there is any difference I would say the VOIP is superior to the old land line I used to have. I also do a part time job that involves twenty or more hours a week using a “softphone” VOIP system. It gives a little more trouble than my own personal VOIP phone but all in all it is reliable and seems to be becoming better and better as time goes by.
The first time I tried VOIP many years ago it was awful, simply absurd in its total lack of reliability but if you haven’t tried it recently you might be surprised.