Ubisoft is "concentrating at the moment" on Assassin's Creed: Origins, rather than a new entry in the once-annual franchise — which is probably a good thing. Ubisoft announced back in 2016 that they would not be making another Assassin's Creed game that year because the one they were working on required "more polish." And what we did get really did turn the once-typical franchise on its head with pretty satisfying results.
Replying to an earnings call question asking if the series would return to a new-game-a-year release schedule, Ubisoft CEO Yves Guillemot said:
"We are concentrating at the moment on AC:O, for which we are going to launch a few other DLCs. So you will be amazed by what will come on AC:O. That's the only thing we can say now."
Guillemot went into some depth about the success of Origins, explaining that it is "is on track to almost double players' playtime versus prior Assassin's Creed titles." Ubisoft Executive Director Alain Corre called it "the successful comeback of the Assassin's Creed franchise."
The company clearly puts the success of Assassin's Creed (and its other 2018 games) down to slowing down production on the whole. We've seen that work with Origins, and Guillemot seems to be banking for the same to be true of Far Cry 5.
"With more time to polish our games, we have been able to release three high-quality titles since August […] We have fully embraced the significant increase in resources required to develop ever-bigger games."
It seems the company's general push towards earning money through "service" games such as The Division and Rainbow Six: Siege has also allowed for more polish in more self-contained games such as Origins which is certainly one way to overcome the limited profitability of single player games in today's games market. And for now, that approach appears to be working.