McDonald admitted on Thursday that Australia's worst performance at any men's World Cup for 17 years had left the side "devastated" but he still emphasised how he believed the team had been good enough to have qualified from their group in Sri Lanka.
His comments came as Australia prepared for their final match in Pallekele on Friday, a dead rubber against the cricketing minnows Oman, with the criticism from former greats still reverberating around the camp.
Glenn McGrath had talked of how Mitch Marsh's side lacked Australia's old "aura" and had a soft underbelly, while Matt Hayden compared their troubled T20 preparations to England's own chaotic build-up to the Ashes.
But McDonald, while offering no excuses for the group-stage exit, was quick to deny Australia's capitulation was down to the country's cricket bosses having their sights set only on the lucrative and successful home Ashes series.
"We've been fully locked into this for a period of time. This is one of our priorities," he said on Thursday about their determination to do well in the event being co-staged in Sri Lanka and India.
"I have heard that sort of narrative that T20 World Cups don't matter to us. I think all that is a response to the performances of Australian cricket teams in these competitions.
"We won in 2021 and we haven't been as successful since then. The expectations on the Australian cricket team are high -- and rightfully so.
"But to sit back and say that we're prioritising other formats or other versions of the game and not the T20 World Cup is entirely false. We've got a pretty devastated group, it's fair to say."
As for the absence of Test greats Pat Cummins and Josh Hazlewood among an injury-hit build-up, McDonald added: "Have we had some challenges on the back of injuries? That's always something we deal with and every nation has to deal with it.
"Unfortunately, (Cummins and Hazlewood) weren't able to make this tournament and does that make a difference to your performance? In some ways yes, but I truly believe that the players that were here are good enough.
"It shouldn't be about the players that we're missing. It should be looking at the performances and we're disappointed in those. We need to own those and the critique is fair and reasonable.
"We've got a room full of players that are incredibly disappointed knowing that they were good enough to progress and we've just got to own the fact that we haven't and that, in all three facets of the game, we didn't find the small margins that would have got us over the line.
"As a collective, we haven't been good enough."
But while explaining the real post-mortem won't happen until the team returns to Australia on Saturday, McDonald reckoned it was important that they bowed out with a win over Oman.
"Last couple of days, there's obviously been a lot of emotions flying around and our job as a coaching staff and as a playing contingent is to be able to zero in on the game," he said. "And it's an opportunity to play for Australia."
