I’m not suggesting we go back to wire and a loop… or just a cardboard box, unless that’s what the kid asks for. That said, you don’t need to spend thousands to keep a kid and their friends happy.
Evidence you demand? Evidence you shall have.
All you need is a little dish soap (do they make that stuff biodegradable now?), water and one of these sweet, sweet, multiple ring bubble makers.
You don’t have to break the bank to bring the kids to your yard.