His side had been playing the kind of entertaining football the fans and owners had been craving and had made their best ever start to a Premier League season.
But injuries, and in many fans' eyes Allardyce's decision to change a winning team when he rested five first team players against rivals Chelsea on Boxing Day, led to the start of an alarming decline which has seen the East Londoners win just three times in 20 league matches.
The goals have dried up, the wins have dried up and so has the entertainment. The side has also developed a costly habit of conceding late goals which has all combined to make for a hugely disappointing second half of the season.
That has led to intense speculation over Big Sam's future at Upton Park with his contract due to expire this summer.
The 60-year-old has staunchly defended his record over four years at the Boleyn.
But he admitted in the wake of Saturday's 2-1 defeat to Everton, yet another game where the Hammers squandered the lead, that the season simply 'crashed'.
"It’s happened again and I think that the players are learning hard and fast since the turn of the year, when we were on the crest of a wave for so long,” the manager told West Ham TV.
“We’ve come crashing down and realised the level we are playing at and the mistakes you can’t make because they will be punished."
The former Newcastle United and Bolton Wanderers boss said the season had provided a harsh lesson for his squad, but conceded they only have themselves to blame.
He added: "There have been some hard lessons learned by the players – especially the younger players and the players who have joined us from abroad.
“I’m really disappointed for the players because they didn’t deserve that, but they shot themselves in the foot.”
Earlier this week Big Sam said he was the man the club needed to lead them into Europe next season if, as expected, they qualify through the FIFA Fair Play standings.
But defeat to Everton pushed his side down to 11th place, not only way below the club's revised target to challenge the top six, but even below Allardyce's own aim of finishing in at least 10th place.