Fire Emblem 3 never saw an official English release either, but I have a converted cartridge of that. Though the English translations are hit and miss with the names, it works nonetheless.
FE 1-3 do have shipping, it's just not a game mechanic. It's tethered to the game's script instead. Marth x Caeda, Julian x Lena, and Astram x Midia exist, and Nyna x Camus is a minor plot point in FE1. Alm x Celica and Zeak X Teeta are in FE2.
FE3 has Catria's and Tiki's unrequited love for Marth, and Abel x Est. The Nyna x Hardin pairing is the instigator of the entire plot, with it being a loveless political marriage that the antagonist uses to influence Hardin into doing his bidding. New Mystery of the Emblem did expand to include supports and pairings, but it's as selective as PoR and FE7 are.
FE1-3 were probably held back by hardware and in 3's case inexperience with the hardware to work in supports, so they just tied it to the narrative instead. FE4 is when supports kicked into full force.