And will for 3-5 more years. That's just the deal in the public US k-12 education system, and probably k-12 everywhere.
No, not everywhere. In France, schools use the latest versions of firefox and/or chrome. It's possible, it works and it's fine.
Also, Flash canvas is "FLASH". It's not HTML5, HTML5 is the promise to get rid of annoying ressources taking plugins to download and install.
Having a ******* version running in an inferior outdated web browser is no performance, only scamming.
You're right that C2 is the perfect tool to make small/easy educationnal games.
It is, in modern browsers for which it has been thought for and designed.
If you want to invest, invest in the training of the network/computer responsibles in schools so that they update their software (OS, browsers) to provide better browsing/learning for the pupils and risk less security issues than with obsolete bastarized hacks.
Firefox and Chrome are free (as in "COST NO MONEY"), why not simply use them ?
And the publishers, inform them about the current status of HTML5 games, convince them that they would bet on the future and it wouldn't represent much investment.
THAT'd be a smart business and responsible/future oriented move.
And you could still make your hundreds of thousands of $ out of the kid's education.