Couldn’t Norway just change their tax code to be based on citizenship and not residence if it truly became a problem?

Then people renounce their citizenship.

That would be preferable because then they would lose all legal protections and other benefits provided by their country. FWIW the US taxes its ex-pats that live abroad.

It's not fair though - part of the reason we have taxes is to take from those who have benefitted the most. Residence implies they're making use of the cities, laws, safety, infra, welfare, etc.

It still makes a little sense if it's a Norwegian living in Sweden, operating businesses in Norway, utilizing Norwegian grants, etc. It doesn't if it's someone who was born in Norway running a business in Thailand.

I think the only country that taxes based on citizenship might be the US.

They still have access to and are making use of all the non-tangible benefits of their country though (e.g. legal protections, rights, any kind of social services, etc). If you want to be a citizen of a country you do have certain obligations to meet.