Because we're tired, also a lot of these games and storefronts make it difficult to lockdown while remaining functional because they want kids to spend their parents money.

But also, my kid has bought crap on games and my response was "hey don't do that unless you ask first, it can cause a lot of problems for everyone" and didn't go straight to punishment mode and escalate everything so that they went and spent 100 bucks on bullshit out of spite. As a parent I can say that this will work 100% of the time, because all kids are like my kid, and if you don't do this you are a bad parent.