I wasn't bringing in the point of minimum wages to suggest that everybody was on that, but just to show that the range of income is very wide. There are also people who CAN afford a 1000 pound weekend in France, but most cannot. The 40 Euros an hour you get from teaching is very good, and I'm sure your time is worth much more than six pounds an hour.... and if you have 5 or 6 people on a course you'd be getting perhaps close to the 40 Euros. However, I can't be spending more than I'm earning, and that goes for most of us (remember Mr Micawber?) 6 pounds an hour may seem peanuts to you but it's food, transport, taxes, rent, council tax, electricity, gas and all the other bills for a couple of million people. No wonder most of us need two jobs.
I thought I'd have a quick look to see what's available and the costs, so I just picked up my nearest photo magazine and came across "Gower Photographic"..... worth looking at
this page and seeing what's included.... 490 pounds but
including accommodation, breakfasts and lunch. So your estimate for France is above (but quite close) to the going rate.... but travel to France plus food and accommodation may just push it too high for many potential punters.
Perhaps I should have commented on just the content of the courses - and not mention the charges - but you asked.