Well, regulation of airfares is no longer in the powers of the CAA or any EU member state. And good thing with people asking for silly things like this.
Far better to have the schools be in session 12 months of the year and to let parents and teachers choose when to take their vacations just like in business. No doubt you would still have peak pricing at Christmas or Easter, for example, but not everyone would choose to go then. Forcing everyone to go at the same time causes peak pricing.
Or they could stagger the holidays county buy county, like the French/Swiss do and smooth out the peaks.