I really don't understand how so many people can adamantly say that Meltan is a gen 7 mon. Has no one ever seen pokemon be introduced early before? Every gen has seen at least 1 pokemon introduced early, but every pokemon's generation conincides with the 1st generation it was available in a MAIN SERIES game. Pokemon Let's Go is not a main series game. The main series switch game is coming out next year and it will be the first of the 8th generation. If we count side games then Munchlax, Lucario, and others would be gen 3 since they appeared in the OG mystery dungeon games. Even if you don't want to count those, you can actually battle with a Bonsly in Pokemon XD, yet Bonsly is a gen 4 mon. If Meltan cannot be obtained in SM or USUM then it is NOT a gen 7 mon.

tl;dr if you think Meltan is gen 7 you are a fucking dumbass