Though taking an early lead through Alex Gersbach, the Wanderers went into the halftime break at CommBank Stadium down 2-1 through goals from Luka Jovanovic and Juan Muniz.
And while Angus Thurgate briefly brought them back level early in the second stanza, a second from Jovanovic and a strike from Panagiotis Kikianis saw them fall to an 11th defeat of the campaign and remain a point adrift of Perth at the table's foot.
"I'm really disappointed with that one tonight," a furious van Egmond told Paramount post-game.
"The actual constitution of the team is very poor.
"Tactically, we had an idea of exactly how we wanted to play, it didn't get carried out by the players.
"The players knew how we wanted to play and there's a core group of players that are definitely on board with it, but, unfortunately, you have some players who want to play for themselves."
As fans increasingly abandon CommBank Stadium amid their side's struggles, reports emerged this week that the Wanderers will seek talks with current Sydney FC boss Ufuk Talay about their permanent coaching role for next season, with van Egmond tipped to move into a technical position.
Despite being one of the best-resourced clubs in the A-League Men and sitting on arguably the most fertile ground for talent in Australia, the club has made the finals just twice since the departure of Tony Popovic ahead of the 2017–18 season and haven't won a play-off game since.
"The whole place needs a real evaluation," said van Egmond, who took over following Alen Stajcic's ouster in January.
"Not only from the perspective of the senior team, but also from your academies up.
"There needs to be a huge evaluation in regards to what's happening within the club and also in regards to what the club stands for."
The Wanderers will have just four games remaining on their season following the March international break to drag themselves off the bottom of the ladder.
And van Egmond said that players, regardless of contract status, were playing for their futures.
"Some of the players, maybe they don't understand that, regardless of whether they have a contract or don't have a contract, everyone's up for discussion," said the interim.
"A new coach will come in; it's not as if that coach isn't watching right now.
"He's going to be talking to the coaching staff regarding who he wants to keep and who he doesn't want to keep."
