The Eagles were smashed 38-19 at the clearances, 14-4 at centre clearances, 60-33 in the inside 50s and 426-278 in overall possessions in the 14.10 (94) to 4.9 (33) defeat.
It marked West Coast's second-worst performance of the season, just behind the 99-point defeat to Adelaide.
The Eagles have also endured poor displays in losses to the Western Bulldogs (76 points), Collingwood (66 points), GWS (65 points) and Port Adelaide (50 points).
But their home loss to Hawthorn - in front of 49,454 fans - was all the more disappointing considering West Coast fielded their best team since 2021.
The return of Tim Kelly and Harley Reid from injury meant West Coast boasted a powerful midfield contingent of Kelly, Reid, Yeo and Reuben Ginbey, as well as first-choice ruckman Matt Flynn.
Yeo, playing six days following the death of his father, was understandably below his bullocking best with just 13 possessions and two clearances in his quietest display of the year.
Kelly had just 15 disposals and three clearances, and Ginbey only 10 disposals and one clearance.
Reid's stats looked solid at 21 disposals and four clearances, but he lacked his usual bravado and polish.
Even Harley couldn't break this Jai Newcombe tackle 😤— AFL (@AFL) #AFLEaglesHawks pic.twitter.com/QG88qWjoJSJune 30, 2024
When asked whether his team weren't as tough as Hawthorn, Simpson replied: "Yeah, absolutely, just look at the numbers.
"I think we're owning this game. There's no excuses, outside of Elliot."
"We meet (on Monday), we'll go through the normal process. We won't treat it like a catastrophe.
"But we've got to dig a bit deeper about the attitude and the mindset of the players as much as what we're trying to chase as well.
"You can point the finger at a lot of players today, but I'd rather you just point it as a collective and it starts with me and finishes with the players."
Adding to West Coast's woes are injury concerns to Flynn (ankle) and Jeremy McGovern (thumb).
Jeremy McGovern takes some deep breaths after a collision with Will Day. (Richard Wainwright/AAP PHOTOS)
Simpson expects Flynn to miss at least several weeks, while the Eagles might need to sent McGovern in for scans to determine if there is any serious damage.
McGovern was his team's best on Sunday with nine marks and 20 disposals, as well as a goal.
"He's tough isn't he? He gives his all," Simpson said of McGovern.
"He's probably in All-Australian form to be honest with what he's got to deal with sometimes.
"He had it (his thumb) strapped up but he didn't come back on. I don't know how that's going to go."
West Coast (3-12) will be back in action on Sunday when they take on Melbourne at the MCG.
