At what point does society get to tell people "you know what, knock it off"?

In other countries, much, much later. And they have less crime. Blanket laws with such severe penalties always have more downside than upside. The ability to dispense such severe sentences should be in the hands of a judge that can weigh each case individually.

If you believe someone deserves life in prison for two burglaries and a case of theft, you are being inhumane. You need to change the system or these people, such that they don't feel the need to steal. That takes time and several moments to check whether it worked. Hell, most countries don't even have true 'life in prison' sentences and they manage to be safer than the US.