As far as I know people move to Spain when they retire because the cost of living is much lower there.
So they get their pension from the country they are from and the pay Spanish taxes since the line in Spain.
So they avoid the tax in their home country which often is higher.
It’s ok if you want to think that there is an enormous tax fraud going on, it doesn’t matter.
Are you sure they don’t?
No, that’s why I said, that it sounded like tax fraud. So, now that you distracted from it, back to the topic: Are you sure they pay taxes in Spain?
As far as I know people move to Spain when they retire because the cost of living is much lower there. So they get their pension from the country they are from and the pay Spanish taxes since the line in Spain.
So they avoid the tax in their home country which often is higher.
It’s ok if you want to think that there is an enormous tax fraud going on, it doesn’t matter.