The thing is, cell phones are so cheap now. Tmobile offers 1000 minutes a year for $100, get a cheap GSM phone (~$10) and that's $110 for a year of service. If you hardly use minutes you can roll them over for another year of service for $10 (which adds 30 minutes). Say you only talk 20 minutes a month (240 minutes a year). Lets consider the cost of 10 years of service. That's a total of 2400 minutes, which would require two refills of $100 (1000 minutes), leaving 8 years that you can get by with the $10 refill (30 minutes). That gets you 2*1000+8*30=2240, which is a bit short, so I guess one of those years you'd do a higher refill than the $10. But lets just call it even.
So total cost is 2*$100+8*$10=$280 over 10 years. Which comes out to $2.33 per month
Lets say you talk even less, about 5 minutes a month (60/year, 600/ 10 years) on average. Then you wouldn't need that second larger refill. So the total cost would be 1*$100+9*10=$190 over 10 years. Which comes out to $1.58/month
Page Plus (which uses Verizon's network, so coverage is pretty great for the most part, and you can use nearly any Verizon phone. So pick up a cheap one used) has similar plans. $10 gets you 100 minutes that last 120 days, there is also a 50 cent monthly charge. So one year costs 3*$10+12*$0.5=$36, or $3/month.
If you talk a lot, Page Plus offers 2000 minutes for $80/year, for a total cost of $86/year or $7.17/month.
If you want a smartphone and want data, there are plans in the $30-$45 range from various providers (Straight Talk, Virgin Mobile, Page Plus, Tmobile, etc)
So for between $1.58-$3 /month you can get minimal cell phone service. Now if the advantages of a cell phone aren't worth that cost, then go ahead and continue not using a cell phone. But don't kid yourself into thinking the only options are "No cell phone" or "$90/month smartphone." There are still plenty of cheap options out there.
edit:
And to answer the original question. Yes I could make do without my cell phone. I make few calls except ones to my wife. However I rely on wireless data for some extra income. Whenever I stop by at Target/Meijer/Goodwill I check for things to resell by looking up what they are worth on Amazon.com. Last year I made about $6k doing that (and I was only seriously doing it for the last half of the year). So it more than pays for the cost of my service ($25/month for unlimited text/data and 300 minutes with Virgin Mobile. The plan now costs $35 for new subscribers, but I am grandfathered in)