That's an interesting take on it. I'd always thought it was because: when ATMs were first introduced, people thought of the cash as more important than the card... Nowadays, I'd say the reverse is true for most people: I've occasionally started to walk away from the machine, stuffing my card into my wallet, only to be drawn back by the whirring sound of the cash counter... People are too set in their ways to reverse it now, but perhaps they could give us both cash and card at the same time?
Giving people their cash and card at the same time would open them up to a scenario where an attacker can just grab whichever they don't reach for first.
From working a few different jobs in retail, I can say it is not to uncommon for people to walk away after paying, leaving their just-purchased items behind.
