You're not taking into account population density. Russia's population is very heavily concentrated in relatively few areas... Not much need to blanket all of Siberia with cell towers.

Same as the US surely? There's huge swathes of the US which has very limited cell coverage. Looking at a map, the majority of OR/ID/MT/ND/SD doesn't have cell coverage, not even 2G. Apparently more than 83% of the US population lives in urban environments, compared to 73% in Russia. In fact, it's more than the UK too (80%).

To some extent, definitely. But America has always had the "open road" attitude. I think it's a lot more likely for a family to take a road trip to the Grand Canyon one summer, across several of those states, than for a Russian family to take a road trip to... hell, I can't find a city in the middle of Siberia on Google Maps, but you get the idea.

I'm sure the Russian roads have coverage too. You're not going to cover places where there is no need to. Many of these areas will not have seen people in decades in Russia I'm sure.

Anyway, it's a moot point. Rural areas are cheap to cover. Stick a macrocell up, microwave some backhaul in from another tower (until you hit the nearest fibre line) and jobs done. Cities are much much more expensive - costs more to put the masts up, need many many more masts and complex frequency allocations, buildings blocking the line of sight, etc. I'm sure that rural capex/opex is a very small percentage of Verizon/AT&Ts budget compared to all the thousands of new 4G sites they're putting up in urban areas.