Well, I know that you and me are not in the same corner when it comes to optimism, but I'd say if we get a CB and ST (unlikely) we have a decent chance to win it, with one of them (possible) then I'd say we have a shot at it. If we don't get anyone else bar Xhaka we still could but it might not be entirely in our hands as of today, but for me that's enough to get excited.
Consistency frequently wins the league, remember how United could play shite and still win it with a bunch of 1-0 wins? If the rest don't get their crap together properly we can W/D at home and D/L away to the other threats, do a United and finish with -something like- 23-10-5 and ~80p -If- the league turns into a brawl where all of the other top teams beat each other left and right and we end up benefitting from it, but that is probably the condition.
atm I fear Chelsea and City more than United as I don't want to think that Mourinho can sort out the mess that is United this quickly but he is quite good at what he does if he is given what he wants so I'm not betting a lot on it. I don't want to think that Liverpool or anyone else are really in it, but it is just wild speculation.