IDK - I think it’s relative to the age of the child and the child’s desire to be part of the competition world. Not Mom’s desire for the child to not “miss out” on anything in the competition world because it’s inconvenient for Mom to haul the big rig around. Mom’s made it clear that she will be using the trailer for her own horses as well.
@Wanderosa made good points wrt what else can be done with $200 a month. I hauled kids around in an old trailer with hand me down craigslist ponies. Any extra money went into the college fund or my retirement account. Little bits of money that I put away years ago have worked very very hard to become much bigger bits of money and allowed my kids to graduate from college debt free. Being a single parent is hard, and your kids usually hang around long after age 18, which is when mandatory child support usually ends. Although my ex and I had an OK relationship, he contributed very very little once they turned 18.