It's probably a number of factors:

- The US remains relatively high income / high wealth. Especially among the more vulnerable senior population.

- The regulatory environment in the US hasn't been successful, or much interested from appearances, in taking on spam.

- Uniform language. Virtually the entire country speaks a single language, English. That's roughly 300 million targets (minor children generally wouldn't count). The largest single European nationality would be Germany, with a total population of 84 million. It's not even possible to necessarily presume an entire country speaks one language, as with Switzerland. And though computer-generated calls are increasing in prevalence, most still use human speakers.

Effectively, it's opportunity, mechanism, and logistics.

But as costs fall and voice-processing (both comprehension and realtime generation) improve, I'd suggest increasing your vigilence around telephone hygiene.

My understanding, from the last time I looked into this, is that the US does have decently aggressive laws against spamming people without offering them ways to opt out and some prior relationship, but a bunch of the spam originates in places outside the US and its immediate allies, so shutting it down becomes nontrivial.

I have, in fact, gotten periodic spam calls, though only once or twice an SMS - usually trying to solicit me about my car's insurance policy having issues (I do not own a car).

I sort of wish I could convince my Android phone to treat all calls to my direct number from anyone but GV as spam, because I have never given that number to anyone.

I’m also in the EU and received a spam SMS not even five minutes ago. I get maybe one a year, so your point stands. Cold sales attempts used to be more frequent, but after blocking a handful of numbers they stopped.