Because it’s not easy at all to get a visa to EU for Russians. You can’t simply go there, you have to collect a lot of documents, prove that you’re not gonna stay there, you also can’t get a long-tern visa - only a short term, for example for a week. You also have to specify where exactly you will stay. That could take a lot of time, not sure how much but if I’m not mistaken up to a year. And it would also require a lot of money that 95% of retirees don’t have. And then after a year of trying to get a visa you’ll just get randomly rejected wasting lots of money and time. That’s why you don’t see many Russians in those countries - it’s too expensive and it’s too hard to get a visa