Not really
"Actually, I'm sure the *real* truth, this being Verizon and all, is this: Verizon doesn't / didn't want / actually spend the money to upgrade their complete nationwide system. There are coverage gaps in the 4G, and therefore most certainly the 5G, network. Telling the world you're killing off 3G essentially cuts off the customers in those areas."
Nope, they finished their 4G rollout (coverage-wise) over 5 years ago, in present day their LTE coverage actually exceeds the coverage of their 3G network. The only spots you'd see 3G/1x now -- fringe coverage, where it might show 1x but it's not strong enough to use (I've seen this), off hiking in some hills... you move to a hair better signal and it flips back to 4G LTE. And if someone still has a 3G network extender (this connects to house wifi or ethernet and broadcasts a 3G signal).. so households with this would need a 4G extender but those have been out for years and are under $200 (perhaps Verizon "should" at least give a discount on the extender but they probably won't.)