I think the unanimous consensus at the beginning of the season was Top four minimum for him, which was fair, yes it's a squad with lots of faults but it's still a good one, better than Liverpool, Spurs and Everton for sure, and arguably on par/slightly below Chelsea and Arsenal. It's certainly one that should be very capable of top 4 despite having a new manager but also clearly isn't at the level required to beat that Man City team to the title.
Suddenly we're doing shit and people are changing their expectations around, it's ok to miss out on the CL, it's ok to finish 7th or 8th despite having a far better squad than most of the teams who could finish above it. Why? The main reasons I've heard to back this up are because Moyes needs time, the squad needs improving, and we gave him a six year contract. All well and good but surely there needs to be a middle ground too, there needs to be a certain level of trust in the manager himself, which is hard to give right now considering our situation.
I think if we finish outside of the top four, he should still get another transfer window and be given a hefty budget, but anything beyond that should be open to how we're doing next year. If, for example, at this time next season, we're still sitting in this position, I'd definitely want him gone. People can call me a spoilt brat for that (and I'm sure they will) but it's more so because I think at that point he's been given enough time and that clearly he hasn't shown himself to be capable of taking the mantle at our club.