When you consider that there are now four-six teams who are going to be wanting to compete for/win the league every season now though, it's pretty much guaranteed that at least one or two of them are going to be fairly inconsistent - even if Spurs fall off a bit next season, it's unlikely Chelsea, United, City and Arsenal/Liverpool will all finish with more than 80 points.
Depending on how things go at Spurs Kane/Alli/Eriksen may want to leave eventually, but barring an offer from Real/Barca/Bayern, who they're not probably good enough for yet to start regularly, I'm not sure where else they can go that gives them a definitively greater chance of success than what they've got now at Spurs: domestically there's no side Spurs haven't finished ahead of in the past two seasons, meaning the only significant, undisputed incentive to leave would be for more money. And I'm sure they're already on big wages anyway.