From a business viability point of view the holiday companies and hotels etc. have little choice but to have higher prices in the school holidays, and to lower them to try and attract custom during term time, when fewer people will want to go away.
I agree that foreign holidays are not an essential. When we were young (here we go!!) we did have foreign holidays because we slummed it in a big tent (and I mean slummed it!) and we went to France, Germany, Italy, Switzerland in the school holidays but very much on the cheap - we did not once eat out, for instance.
When our children were at primary school (teachers close your ears!) we regularly took them out of school for two weeks each year, as my OH could not take his holidays in the summer. It did them no harm whatsoever; in fact it enhanced their lives and learning in a myriad of ways.
Given the high pressure environment of schools now, I should think that taking them out for a holiday is a positive thing to do.