Why should you change the rules and penalize the teams that actually brought the right tires?
Teams are allowed to bring backup tires in case the inital set does not function properly. Why didn't Michelin supply the teams with backup tires? Moreover, as Derek Daly said during the race, the IMS has been here since 1909. You'd think Michelin would have had plenty of time to make a tire that could go around the track 73 times.
On top of that, there was nothing preventing the Michelin teams from racing on the new tires flown in from France on Saturday--there just would have been a penalty from FIA for doing so. Why didn't the teams run on the new tires and take the penalty?
It's not FIA's fault. The rules are there for everyone to understand. It's not Bridgestone's problem (or Ferrari's) that Michelin didn't build a tire that could run at Indy.
It sucks for the fans, it sucks for Indy, and it sucks for the IMS, but change the rules? No way. The teams had plenty of options and chose not to take them.