Forward Josh Kennedy booted five goals in the first quarter to set up the 20.12 (132) to 3.11 (29) romp at Domain Stadium, with the Eagles never challenged after kicking the first nine goals of the match.
West Coast have won all five of their home matches this season, with the average winning margin a whopping 66 points.
But the Eagles have wilted in all three of their away games, losing heavily to Hawthorn (46 points), Sydney (39), and Geelong (44).
West Coast have the chance to momentarily silence their doubters when they take on the struggling Power at Adelaide Oval on Saturday.
Simpson is becoming tired of the questions relating to his team's poor away form. But he knows he's going to keep copping them until the Eagles start winning on the road.
"We're not going to change too much. I think we're not far off," Simpson said.
"But until we break the duck on that one, you're going to keep asking questions and I'm going to keep defending them.
"It wasn't one of those soul-searching weeks (after losing to Geelong).
"It's just a long year, so for us to rebound and play well (against St Kilda) is pleasing. I'm happy with the margin, but we've still got some work to do."
Although Kennedy failed to kick a goal after quarter-time, Mark LeCras (six goals), Luke Shuey (31 disposals), Andrew Gaff (36 disposals), and Nic Naitanui (33 hit-outs) ensured West Coast continued to hammer St Kilda on the scoreboard.
The victory was West Coast's largest ever triumph over St Kilda, eclipsing the 95-point margin they beat them by in Perth last season.
St Kilda coach Alan Richardson was stunned by his team's inept display, especially after they came close to toppling flag fancies Hawthorn and North Melbourne earlier this season.
"I didn't see that coming," Richardson said.
"They just smashed us. We just couldn't cope with their attack on the footy and their attack on us when we had on the ball.
"We can't just pretend that this is just an aberration. This was real. We need to learn from it."
Saints skipper Nick Riewoldt tried his best to stem the damage by roaming to all parts of the ground, but West Coast's dominance of the midfield battle meant the result was only ever going to go one way.
Naitanui's brilliant tap work against Saints big man Tom Hickey helped set up the first-quarter onslaught, with the scoreboard reading 57-1 by the time Kennedy kicked his fifth goal.
Hickey finished with 26 hit-outs from 11 disposals, but Richardson was scathing of the 25-year-old.
"It's frustrating. We've got some pretty good players in there. That was Hickey's worst game," Richardson said.