Spain is the largest producer of citrus fruit in Europe. All those grapefruit (and pomelos - Spanish for grapefruit generally
) must go abroad. Rare to see them on the shelves. Not for Spanish taste buds. Just a different variety of grapefruit.
Here in Portugal There is a citrus with red flesh that someone called a Spanish grapefruit. There is also a white orange - laranjabranco. Confusing.
Caqui as opposed to 'Persimon' were my favourite short term native seasonal. That comes second to mandarins fresh off the tree at 50 Cents A Kilo on the street.