That is down to how each County has advertised it out in the first place.
In my County, is it clear from before anyone applies, that each one of the 40 people is fundraising the total for 40 people to go, so where there are one or two members of the Unit who have struggled to get to the individual total, then more of the 'whole unit' stuff goes to them. It is, obviously, dependent on them all putting the work in and contributing what they can, but clearly individual families are in different positions in the first place and have different people in their social circles, etc.
The same as if someone decided they don't want to go (sorry, can't remember who asked that) - when they sign up, they understand that any bag back / car wash / quiz night / dance / cake sale /badge sale etc is funding the Unit to go.
However there are completely different ways of doing it - so other Units will have done it differently. There are many units where the parents pay for it all (usually installments). I think most units do a mix of parents contributing some and fundraising for some.
Obviously those that are chosen get the most fantastic experience, but much of the money all the Western Countries raise, pays for all the infrastructure, and pays to allow all the Countries in the World where there is Scouting, to send a contingent. There is Scouting in all but about 6 countries in the world. More countries attend the WSJ than the Olympic Games (if you have ever watched an opening ceremony of the Olympic Games). Scouts from many of those countries are only there because the Scouts from USA, Canada, Europe, etc etc raise the money for them to go.
We always say that Scouts should offer 'something' in return for money - as others have said, getting your car washed, or your lawn mowed, or a lovely cake, or some babysitting. Or, they should put on events that are a great evening out - a Quiz, a Curry night, a Barn Dance, a Race night, etc etc. Nobody should be just 'expecting' their parents friends to give money.
that said OP, it sounds like this is nothing to do with the WSJ, and everything to do with the entitled nature of your so called friend.