The Austrian feels the 67-year-old deserved a new contract at the Allianz Arena but admitted that incoming coach Pep Guardiola will secure "supremacy"Inter and Roma star Herbert Prohaska has criticised Bayern Munich for letting coach Jupp Heynckes leave after the 2012-13 campaign.
The 67-year-old has delivered the Bundesliga title to the Allianz Arena this season and led the Bavarians to the Champions League and DFB-Pokal finals.
And while the Austria legend feels that Pep Guardiola will ensure continued success in the coming seasons, he believes Heynckes does not deserve to be replaced.
"With Guardiola, Bayern will have a coach who can secure them supremacy in Europe over the years," the 57-year-old told Kicker.
"However, objectively, it's madness to let Jupp Heynckes go after a season like that."
Saturday's 1-1 draw with Borussia Dortmund was just the second game Bayern have failed to win in 2013.