The Scot has seen the Red Devils struggle in his debut season since replacing Sir Alex Ferguson which has prompted calls for his sacking by many outsiders.
However, Moyes' compatriot Macari suggests that the former Everton boss needs to be treated with more patience, especially seeing as Arsene Wenger has failed to win a trophy at Arsenal for nine years.
"It's safe to say things aren't going right for United at the moment and it's not going right for the manager," the former United winger told talkSPORT's Drivetime.
"But David will be given time, no matter how many planes will be flown over Old Trafford.
"If the manager of Arsenal can go nine years without winning a trophy, I'd like to think the manager of Man United can go nine months without people calling for his head.
"If Chelsea win nothing this season, how will you look upon Mourinho? Will it be met the same way as David Moyes in his first year in charge at United? It'll certainly be interesting to see what happens if Arsenal fail to win the FA Cup too.
"David is a football man, he knows what's required and he expects time to do the job.
"United need to improve but it can't be overnight. It's a tough place to manage. Alex did brilliantly during his time, but not every manager is a Sir Alex Ferguson."
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