Those franchises are probably the closest in comparison to something like a Xenoblade though, they are singular platform releases that were big critical successes with multiple entries.
Xenoblade has yet to break out of that low ceiling like other popular JRPG, minus like…’Tales of’ series? Which still hasn’t really hit the highs and level of hype of Xenoblade.
It’s also probably one of the biggest budget and post polished games Nintendo produces. For it to be stuck in that low 2.5m Lifetime sales while pokemon also exist on nintendo and sells like 5 million in preorders alone tells you the market isn’t there to expand JRPG market on nintendo. The typical nintendo consumer just isn’t interested in those big rpgs outside of Pokemon which still feels very much like a mobile centric series.
Its telling when xenoblade has active representation all over the Game Awards and other outlets award list and it’s still selling a tiny fraction that a Pokemon spinoff game is doing on the same platform
Persona, FF, DQ, Fire Emblem, and many others had humble beginnings. Its easy to say now that "Even Fire Emblem or Persona sells more now", but in both cases the first 5 to 10 entries of such franchises didn't even break a million individually.
And in terms of smaller franchises that have several entries, there are plenty. Tales of, Atelier, the HD-2D games(though they have also been growing steadily), Bravely games, Gust RPGs in general, Digimon, Star Ocean, Ni no Kuni, etc.All of them have 3 or more entries, but sell less than Xenoblade, but most of them are going strong in some form or another.
Which brings to my point: Not every franchise needs to be a sales juggernaut, AND not all sales juggernaut is a overnight success.
You mention that Xenoblade is one of the biggest big budget Nintendo games, but we don't know that.Not only that, but " big budget" for Nintendo might not even be a lot of money if you compare to the ammount of money that other companies spend on their games. So success is relative. What matters is if the game is profitable, and its showing growth that the dev is happy with.
And Xenoblade checks both boxes.The first XC 1 sold about 1 million in its original release, and the sequel went from that to what will most likely be 3 million. XC 3 opened higher than XC 2, and everything seems to point to the fact that XC 3 will sell more than XC2. If it ends up on "only" 4 million or go up to 6 million, only time will tell.
But its beyond a doubt that XC is a success as a franchise, and XC 3 is as an individual game. Because of its relative growth compared to previous entries, and how Nintendo seems happy with its performance.Everyone would have wanted that it sold 2 times that it did, but at the moment its simply not realistic.
Until Nintendo says otherwise, that's what the data points towards.