Curious why
hasn’t been upgraded an echo when he was originally gonna become his own fighter during sm4sh was he no longer a priority around ultimate?
Pikmin basically had nothing new during that time period, sooooooo, lower priority.
Also, keep in mind that Pikmin & Captain is the actual character. Those little buggers are quite important overall, so even if you can Nolimar(rather poorly now. It was easy in Brawl, but come 4 and Ultimate they made the Up B not require any Pikmin out, so it's technically harder to do. Though I don't know if he's competitively easier to go without Pikmin than he was in Brawl?), it's not actually the intended way to play. I mean, not that any way is wrong either, but the moveset is designed so you should be playing with both. We just got a bad translation that misinterprets the characters overall.
The important thing to remember, though, is that with the moveset made with Pikmin and the Captain in mind, making any kind of Echo or Clone means the Pikmin are still an important part of said moveset. So Alph not being separated also has to factor in "why didn't Sakurai see any fun ideas with the Pikmin themselves"? In 4, at least we know that it was too time consuming for a quick clone. Justified in that it was already difficult to make Pikmin & Olimar work properly, reducing the Pikmin themselves to a max of 3. Rock Pikmin weren't even let loose(albeit, it was designed as an Olimar option, not specifically for Alph), which also implies the Pikmin alone were difficult to program at the time. Come Ultimate, and Pikmin having no new games, you already have low priority. Then you have the question of "what do they want to do"? The only caveat is that Alph outright has no unique abilities from Olimar with at most having different Pikmin choices. And with no new Pikmin being introduced, that also means ideas for a more unique character would go up in smoke.
So either way, you have no moveset ideas and an understandable case of low priority. With Pikmin 4 being a thing, though, we have a fair chance for a new character(it might not be Alph, though at that point, an Echo would be nice. Just add personality to Olimar and Alph, so they have fully unique taunts, and replace the Purple Pikmin with Rock Pikmin, including some differences in how they affect gameplay, and you're set for an easy enough one. Maybe).