I'm with Shamu, here. Pay for what you use, instead of trying to squeeze an "unlimited" square peg into a finite round hole.
So Verizon just needs to bill $0.001 for every MB used, and everyone would be happy. No bullshit about tiers, overages, etc. If you're on WiFi all month, your cell bill would be $0. After all... "At the end of the day, carriers don't need tiered plans." Tiered data just "doesn't work in an LTE environment."
That leaves some paperwork/billing issues, but they're easily solved by only sending out a bill after a subscriber has accumulated at least $5 in charges, however many months that happens to take... Telna is a cheap wireline long-distance service that bills customers just like that, so it works.
And don't worry about voice minutes, as they're just small streams of data, themselves, and can go over WiFi as easily as it can cellular, leaving you again with a $0/mo bill when you're staying on WiFi all the time.