The Hammers are enjoying a terrific season - sitting fifth in the Premier League, in the knockout stages of the Europa League and set to face Kidderminster Harriers in the fourth round of the FA Cup.
Yet the squad have shown signs of creaking under the pressure of competing on multiple fronts, with back-to-back defeats to Leeds United and Manchester United underlying the need for strength in depth.
As the 11pm deadline on January 31 sailed past, the club failed to bring a single player to the club - despite Michail Antonio being the only senior recognised striker at the club and Angelo Ogbonna likely to miss the rest of the campaign.
Critics have already suggested star man Declan Rice is now more likely to leave in the summer due to the lack of investment, while others are more concerned about the immediate end to the season.
Yet Moyes admitted he was happy with the squad at his disposal, despite seeing three club-record bids rejected.
"It was a late night," he told the club's YouTube channel. "I would have loved to have said we'd got everything done and dusted early doors.
"Look, it wasn't for the want of trying, that's for sure. West Ham supporters can be reassured that we were really ambitious in trying to get good players and players who could help us and make a difference.
"We've also got Jarrod Bowen and it would be very hard to get a better back-up to Micky Antonio than Jarrod.
"Overall, all I can say is that the board have been fantastic. We probably made three record transfer bids from the club in this January window and, let's be fair, January is never really a great time.
"We've been quite good in January in the main and in the last few January's we've been here we've signed good players and sort of done quite well, but this one for some reason became tougher.
"I also believe it's probably been tougher because we're looking at a much different level of player now and trying to attract some of the top players throughout Europe."
Darwin Nunez and Duvan Zapata were strongly linked with moves to bolster the club's attacking options, while Duje Caleta-Car of Marseille was also mooted.
Dissension aimed at the club's board for failing to increase the squad's quality and quantity naturally followed by irked supporters, yet the Scot was having none of it.
"I have to say there's been some things said about the board, but the board in this transfer window have been brilliant," Moyes added.
"They have backed me and tried to support me in all the moves. I've got to say, the work Karren Brady has done to try and see if we could get some deals and get things happening, she's been really good.
"David Sullivan's been really supportive, Daniel [Kretinsky] has just come in, and David Gold - they've all been really good in helping me over the window.
"So it's always good when your owners are helping you and trusting you as well.
"We know we're growing, we're going the right direction and hopefully we can keep that going."