Which country? I am in Finland and have had the same number for over 20 years. It is publicly listed. I receive maybe 1-2 marketing calls a month and less than one SMS scam per year. I am somewhat restrcitive filling in my contact details when I don't expect any real business. I only use deposable email addresses, but that should be completely unrelated.
That's your answer right there. Finland is a small country with a very niche language of just about 5M people - it's too expensive to teach people Finnish good enough to convincingly scam off the elderly, not enough marks to return that investment, and you need a sizable population of poor and desperate/dumb people to act unknowingly as money mules.
In contrast, for English language scams, you got 340 million Americans, 68 million Brits and dozens if not hundreds of millions of people speaking primarily English in former colonies (India, Australia) that are potential marks. And to make it better for Indian scammers, people there are already used to Indian call center accents so their alarm bells don't go off immediately.
For German language scams, it's 84M in Germany, 9M in Austria and 4.4 million German speakers in Switzerland. For us, it's mostly scams based in Turkey, because there are a lot of Turks who learn German because they have relatives here or their parents had a stint in the 60s-90s.
We've also had a couple generations of folks trained to treat 'foreign' sounding speakers as authoritative, due to most call center and support work being shuffled to non-US-based places. Calling a 'local' cable company and getting someone in Phillipines or India giving support is the norm, and many folks are now accustomed to giving details and account authorization for things to people who sometimes can't form coherent or natural-flowing sentences.
Just read [1] that our local telecom authorities (NKOM) report good progress when it comes to preventing people from abusing Norwegian telephone numbers to spam/scam Norwegians.
Sweden here, and I get less than one spamm call per year I would say, likely from abroad since in Sweden you can easily opt-out of marketing calls, except from companies where you are already a customer, which can be annoying enough.
My work mobile number is listed on the company website. I need to answer unknown calls from anywhere in the world, although I only get them every two months or so.
I can easily look through my whole call history. This year I seem to have had about six spam calls, and for the first time I bothered to work out how to block a number on Android — three of the calls were from the same number within a few days of each other.
I'm curious how this works in the USA for people that need to answer work calls — does the receptionist at a large company find 9 out of 10 calls coming in are spam? In some countries there are specific ranges for different types of numbers (all UK mobile phone numbers begin with 7, all numbers beginning with 3 are businesses/etc) which allows the spammer some basic filtering, but that's not the case in the USA.
The last "Microsoft" support call was years ago.