>>48433472I'm just going to ignore you having second thoughts midway through your post about whether it's impossible to have another game with all pokemon in it for a moment and point out how unlikely it is that Basculin(and by extension Basculegion) is never leaving home post-PLA.
Basculin never making it into a regional dex or some expansion like swsh's DLC in the event of no national dex ever again is unlikely given that's only happened to the likes of Glameow and Mew, especially since Basculegion is on track to be the most popular pokemon introduced in PLA. The most likely way of never using Basculegion in a game post-PLE is some blanket cutoff of pokemon from Hisui, which is unlikely given there's regional variants, which have been allowed in whenever another form of them are also in. Suffice it to say there's no precedent for permanently locking an entire species out of the loop, just a form of existing pokemon like Floette, Pichu, and Pikachu. This is also ignoring that Basculegion is a straight-up crossgen evo as opposed to a Hisuian form/evo since it's listed separately from Growlithe and Braviary. Depending on how Basculin evolves, Gamefreak could also just do what they did with magnetic fields and change it to a dusk stone evo or something. Pokemon like Runerigus aren't locked out of the loop despite locaton-based evos. Each subsequent game's regional dex is just a dice roll if a given pokemon gets in.
Also given the inevitability of a unova remake(which got Glameow in a new game btw), Basculin, and by extension its crossgen evo, are pretty much guaranteed to come back if it's mainline like every remake to this point. At worst, they'll pull an FRLG and not let it evolve until postgame.
