I think it's a mindset thing.
If you've worked when your children are pre-school age, then you are so used to paying shedloads in nursery/CM fees, that you are grateful when your children reach school age that at least 6 and a half hours per day is free!
If, on the other hand, you don't work until your kids are in school, the holidays hit you with a shock and you feel you're spending all your income on childcare. You're not. You just have to balance it out over the year. Yes, you may spend most or all of August's income on childcare, but overall, you're making more than you're paying (which isn't necessarily true when you have pre-schoolers!)
As for logistics, split holiday leave between partner and self, at least some of it, seek out holiday care, clubs etc.
Someone made the point that some holiday clubs only run 10 to 3, and not normal working hours. But then if you need care from 8 til 6 or whatever, then presumably you already use a CM during term time, as you would need to use before and after school care, so maybe worth checking whether your CM can do some full days, or knows another CM who would?
None of it is easy, but all do-able if you have to.