Do you hollow out the inside of your Mango tree?

[Homeby5]

Reading different guides to pruning, most seem to agree that you keep the tree hollowed out in center. Basically...a hole in the top. They also keep it under 15 ft tall.
Asking because i see some very dense, full trees in my neighborhood that look beautiful but I don't see a lot of fruiting going on. They have fruit but not as much as I would have expected from such healthy looking trees.