The 23-year-old was one of Germany's most highly praised individuals during the group stage, but he and the rest of the team crumbled in the semi-final as they were eliminated by Italy.
And Hummels is aware there is a lot of room for improvement.
"With the performances we gave at the Euros, I don't think we have a realistic chance of beating the top nations in the decisive games and becoming world champions," he said.
"We have got to get a lot better."
Germany entered Euro 2012 as one of the favourites after winning all 10 of their qualifying matches.
Reaching the semi-finals saw them set a new record of 15 consecutive victories in competitive matches since finishing third at the 2010 World Cup, but Italy laid bare their limitations like they had done in 2006.
Hummels feels he and the rest of the team must learn from such results over the next two years to finally make the step up from being close to glory to actually winning tournaments.
"The big difference was that Italy took far more risks while we placed huge emphasis on being cautious," he told Kicker magazine.
"You have got to recognise that we were the worse team in that game and we would have lost even without my mistake.
"Apart from the Greece game, we were always taking the tempo out of games."