United flattered to deceive once again on Saturday as they let a first half lead slip to draw 1-1 with Southampton in the Premier League at Old Trafford.
The Red Devils have now taken the lead in each of their last three games across all competitions but have failed to emerge victorious.
Rangnick’s side are still stuck outside the top four places amid a poor run of form.
Paul Scholes has described the German tactician as a sporting director and not fit to manage the club but Neville does not believe Rangnick is entirely to blame.
"You put that many ingredients into a soup, you don't know which one in the end is making it taste bad," he told Sky Sports regarding United’s summer recruits which included Cristiano Ronaldo, Raphael Varane and Jadon Sancho.
"You lose your sanity over what's good and what's bad.
"I felt they were near last season [when they finished second] but now I feel they are as far away as they've ever been from winning the league.
"Maybe the right appointment in the summer and a little bit of a shuffle with someone who is calculated, ruthless and knows where the problem lies could change things again.
"Right now, I'm looking at a broth of 100 ingredients and don't know which of them I want to get rid of to make it taste better. It's a mess and United fans must take their medicine."
"It now gets to a point where you don't feel it's down to the manager anymore," added Neville, who won 17 major honours across his near two decades in United's first team.
"Ole was getting a lot of criticism at the start of the season and loses his job and it's now being suggested that Rangnick isn't good enough because he's a sporting director and he's not a coach.
"There's a confidence issue but there's also an issue of excuse mentality and of looking after themselves and not looking at the bigger picture, which is creating a brilliant team and trying to get back up that league."
