I think that was merely an incorrect perception. The US had substantial 4G coverage long before Europe did. As a whole Europe has been far behind on 4G adoption until recently.

The same is true about broadband speeds. It's widely believed, incorrectly so, that the US lags massively behind Europe on broadband. It's not true however, it's little more than a bogus bashing point spread around online. The US has comparable average broadband speeds to the UK and Denmark, and is faster than Germany, and far faster than France, Italy or Spain. [1]

[1] https://www.stateoftheinternet.com/resources-connectivity-20...