Here's how I balance it ...
I, as the parent, provide for the NEEDS of my minor children. That's my responsibility; not theirs.
They provide for a great many of their WANTS. I do some; because I love them, want to do it, and have the ability. But your dh and MIL are right in that children do need to be taught how to provide for themselves, how to use the resources and tools that we as parents have provided. So my children provide for many of their own wants.
Some examples ... I pay for my kids' school lunches. However, if dd wants to join a group of friends at the local pizza place one day for lunch instead, she pays for it with her own money. If we go as a family to the movies, I'll buy their tickets and maybe a drink/popcorn. If ds goes with his BFF, he pays for his own ticket and drink/popcorn. If dd wants a $50 pair of sneakers because it's the cool kind, I might pay $25 (that's what the non-cool kind cost) and she makes up the difference.
How this will pan out when they're old enough to be working, I don't yet know. But I'll suspect I'll allow/encourage them to get jobs to pay for all those "extras", but if they choose no extras, then they can choose no job.