Does a medium rider on a large mount need at least 7.5′ reach to make melee attacks then?

Does a medium rider on a large mount need at least 7.5' reach to make melee attacks then? If they're centered on a large creature, the mount's space extends 2.5' beyond the rider's. Do you usually handwave that away…?

— Armando Doval (@armando_doval) November 8, 2017

If you're using miniatures, your character is wherever your miniature is. #DnD https://t.co/hsASKlASMV

— Jeremy Crawford (@JeremyECrawford) November 8, 2017

so, when using a grid and miniatures you can “fit” the rider any square occupied by the mount? Yes.

— Jeremy Crawford (@JeremyECrawford) November 8, 2017