Just last month during a polarizing Byleth Smash Ultimate reveal, Smash head honcho Masahiro Sakurai revealed a second Fighter's (Season) Pass.
In short, it will have one additional fighter in its pass system (bringing the count from five in Volume 1 to six), and will run "through the end of 2021." At the time, fans assumed this was an end date of sorts for Ultimate, and based on a new Famitsu interview, it might be.
Speaking to Famitsu (as translated by PushDustIn), Sakurai explains that "there are no other plans" for another pass after the second one. It's a very simple statement, but it's a meaningful one. he also notes that there are "no plans" for a follow-up to Smash Ultimate right now, but with nearly 20 million copies sold just on one console, Nintendo won't leave that money on the table.
He follows that up by re-iterating that Nintendo decides who to bring in as DLC, and that while working on Smash full-time doesn't allow him to be as free as he would like with original ideas, it makes him happy to make everyone else happy. For now, he will "give it his all" for the last six fighters.
It's crazy to think the end is coming for Smash Ultimate, but we have nearly two years until that happens. For now, we wait to see how many Fire Emblemand Pokemon characters are taking up those six slots.