Two or three years after Nintendo’s next console releases probably. The next console will be announced this year and will probably release sometime next year, so that would put the next Animal Crossing game around 2027 or 2028. That would be around the same amount of time between games as New Leaf to New Horizons.
Eh, I feel as if 2027-2028's too late for the next AC game? That's a good 6-7 years of
absolutely nothing except for Pocket Camp updates (and given they added the last set of villagers late last week, it
could be coming to a close at some point in the near future), compared to the 6-7 years in between NL and NH where we got HHD and amiibo Festival in 2015, the Welcome amiibo update in late 2016, and Pocket Camp in late 2017.
As I said a long while ago, I don't think we're getting another spinoff (HHD ended up turned into a DLC side mode for NH, amiibo Festival sold badly even by the Wii U's standards, even Aya Kyogoku said it existed for the purpose of making Animal Crossing amiibo figures, and its devs at NdCube Tokyo have seemingly exclusively worked on Pocket Camp for the best part of a decade). Splatoon 3's coming to a close, with what's heavily implied to be its final season coming out on Saturday, and Animal Crossing and Splatoon generally seem to alternate on the release schedules (Welcome amiibo came out in the gap between the first game and Splatoon 2, and NH came out between 2 and 3)... and given it's been referred to as "the third part of the trilogy", I don't anticipate Splatoon 4 coming out anytime soon.
Things seem to be heavily pointing towards
soon for the next game. The Switch's successor's announcement has been announced (all we know right now is that it's not happening in the June Nintendo Direct) The 2024 New Years art feels like it's hinting at the next game in the same way the 2020 Splatoon art did. Pocket Camp's got all the regular villagers now, and is either waiting for new villagers to be added in a new mainline AC game or it's steadily but surely winding itself down. Even the presence of WW's title theme as a "you failed" K.K. song and future secret song seems to coincide with WW's 20th anniversary next November (unless you live in a European country like England, France or Italy like me, in which case it's the best part of 2 years away).
Unless they've done something incredibly stupid, like the AC equivalent of the Mario Kart 8 Booster Course Pass (here's all the furniture from Pocket Camp,
ripped directly from the game so it looks horrendously cheap compared to NH itself!), another party game (NdCube apparently have another game in development) or something else, nah. I don't feel like it's going to take as long as the gap between NL and NH again.
Admittedly, it's
already a longer gap between entries than even the gap between LGTTC and NL (in Japan), so it's probably going to be second place... but I genuinely think we've got a decent chance of hearing about it before the end of the year.