True.
> it's trivial today, even for a non-technical 10 year old
Not even close. It's difficult even for a technical 30 year old.
You're talking about acquiring cash that has passed through several people's hands without touching an ATM that recorded its serial numbers. Using it to acquire Bitcoin from a stranger. Making use of multiple VPN's, and making zero mistakes where any outgoing traffic from your computer can be used to identify you -- browser fingerprinting, software updates, analytics, MAC address. Which basically means a brand-new computer you've purchased in cash somewhere without cameras, that you use for nothing else -- or maybe you could get away with a VM, but are you really sure its networking isn't leaking anything about your actual hardware? Receiving Bitcoin, and then once again finding a stranger to convert that back into cash.
That is a lot of effort.