It's harder for folks to make impulse purchases if they have to take time to locate their credit card and enter the digits every time. This behavior you have observed is by design.
That may be true, but I'm not sure how you glean it just from the observation that smart companies try to make it as easy as possible for customers to spend money with them. Every smart businessman since the stone age has tried to do the same thing.
Sure, it's business pocketing benefits and shirking costs. I'm not saying it's not bad, just that I'm not sure how this relates to "the US consumer economy [being] a massive hamster wheel". It was either a non-sequitor or I don't see the logical connection, if there is one.
In the US, our funds aren't at risk. If someone hacks my Amazon account and steals my credit card info, the credit card company will cover any losses (and presumably go after Amazon to recover them.) The incentives of the various parties are actually pretty rationally aligned here.
So I'll thank you for not making it more of a pain in the neck to buy stuff online than it already is.
Finally someone addressed digi_owl's point that it wasn't about making it easy but that Amazon didn't clearly state the number would be recorded and saved in a database.
Most other non-Amazon shopping carts have checkboxes like "Store this credit card for future purchases" but I imagine we could make better payment solutions by pushing all risk to a QR code (instead of NF) + Apple/Android Pay + payment agreement button on the phone.
