Then ban the VOIP providers. Maybe they'll adjust their policies accordingly.

This is essentially how email works, right?

Legitimate companies who deal with mass email on behalf of their clients (such as MailChimp.com) are very careful to prevent abuse, precisely because of the risk of getting blocked (which would sink them, of course).

I'm using Google Voice, 90% of my incoming calls are spam bots. Ban Google?

90% of everybody's incoming calls are spam bots.

This is true for me, but only because nobody calls me except for my wife, and even those calls only happen when she's on break at work and bored. All my other non-work-related communication is over SMS, Facebook Messenger, or Discord.

I've never been robocalled, but I've had "microsoft support" scammers call me once.

I'm in Sweden. Not sure if the difference between 90% and 0% is technological or legislative.

Presumably if the Swedish tax authority called you, they'd speak to you in Swedish, and you'd be suspicious if they couldn't. So if you wanted to run this scam on Swedish targets, you'd need to find a bunch of Swedish speakers willing to work for low wages doing something unethical and illegal. AFAIK, the only country with significant number of Swedish speakers is Sweden, a fairly wealthy country, and also the country where you'd be running the scam, vastly increasing the legal risk.

On the other hand, there are countries which are poor, not the US, and have lots of English speakers, and these scams tend to be run from those countries, at least according to the callers' accents.