The current system DOES allow it, it’s not a system like the American one, what does not allow it’s the will of the voters, those on the left would be cool with the idea, but they are not going to vote for it because they are not on the left and those on the right do not like a center party. It’s not the system, it’s the people.
It may be, but in the case of Spain the party has not moved, it has always had those positions, both economically and socially, not so much perhaps against immigration, as on abortion or religious issues, they have always been the version most radical of the European PP