When I bought my daughter an iPad, I spent about $200 buying full versions of apps and game, even yearly subscriptions so she’d have lots of entertainment, games, education without being nagged for more money. Less than a month later, none of that mattered. I refuse to be taken advantage of in this way, worse, by using my kids as ransom. How can we fix this?
Educate the parents.
This stuff isn't just harmful to your wallet, it's harmful to your child's health [1,2]. You may as well be encouraging her to smoke cigarettes.
You're the adult in charge. Remove the demand by learning about the many harms of exploitative online digital products for children, the depression and mental illness, loss of focus, irritability, poor socialisation...
Figure out how you're going to pass positive life-stance changes to your kid. Explain to her what the glut of phones and tablets are doing to the planet. Wean her gently off the addiction that is probably already taking hold.
Go riding bikes, flying kites and looking at nature.
Then, slowly reintroduce technology as a useful tool under close supervision.
Why not a stationary PC? It has much more mature and complex games (and Android emulation for "apps"), is open to modding, has proper peripherals and can do general computing. And it being stationary means you have a "physical distinctiveness" of the place.
The mobile (gaming) market is so flooded with exploitative, ephemeral shovelware it stopped being funny long ago...