England head coach Trevor Bayliss says his side have simply not played well for long enough after they relinquished the Ashes in Perth.
An innings-and-41-run victory for Australia at the WACA means Steve Smith's side hold an unassailable 3-0 lead in the five-match series, ahead of contests in Melbourne and Sydney.
While England enjoyed encouraging periods in all three Tests, they were ultimately well beaten on each occasion.
Bayliss told BT Sport: "You've got to give them [Australia] credit. They have played better cricket than us. They've played better cricket for longer periods. We've played well at times in matches, but not for long enough.
"The Australians have shown us that you've got to play at that intensity and at that level for a full five days. That's what they've done better than us."
England are now in danger of being on the wrong end of a third 5-0 whitewash in four tours of Australia, either side of their famous 2010-11 triumph.
With the series now beyond them, calls for a selection shake-up are likely to increase, but Bayliss brushed off suggestions out-of-form senior players Alastair Cook and Stuart Broad could be nearing retirement.
He added: "I think they'd both agree they're a little bit closer to the end than they are to the start. That just happens with experience or the older you get, I suppose.
"But there's absolutely no reason why they can't continue to be a part of this England team into the future."
On the prospects of avoiding a 5-0 loss, Bayliss said: "It obviously hurts every time you lose a game, it doesn't matter whether it's a match or a series. I can assure you the boys are not going to give up.
"We came here with a view to taking it one match at a time and trying to win each individual match when it came up, and that won't be any different come the fourth Test."