Let people break the rule and take the items in their carry-on? (in which case why have the rule in the first place?)
Pay people when they take the items? That is going to be an administrative faf all because people can't read and follow rules correctly - do you want to pay for that admin in your ticket prices?
Allow people to pay for the items to be stored until their return? They'll be accused of profiteering there too because again the admin work will need to be paid for, and there is a logistical problem when people don't return to the same airport.
Just send the confiscated items to landfill?
You might argue that a lot of the security theatre around air travel places a hindrance on the passengers and that you consider it unfair, but the rules about carrying sharp objects are very clearly documented (at least they have been when I fly around Europe, are the US processes less organised?) and well known even if you don't bother to read the documentation, so having such items taken off you if you do bring them in pockets or other carry-on luggage should be no surprise.