Is there anything to stop me from pulling receipts for something I didn’t actually put in my luggage?

Your damages are what you had to spend on all the new items you had to buy for your trip, to replace the items they failed to deliver. You buy new clothes (etc), keep the receipts, and turn those in for reimbursement. At least this is how it worked a decade ago when my luggage was "lost" for a US domestic flight.

In my case, I think they deliberately bumped my bag for paying cargo, because they saw my billing address was near the destination airport and assumed I would be fine "at home". They didn't know I was going to a wedding, and that said wedding was several hours drive away, so delivering my bag a day late to the destination airport wouldn't end the problem. They still paid out though.

aobdev's idea of reimbursement doesn't work in either direction. The price you paid for something is only weakly connected to the thing's current value. But your damages are equal to whatever the current value is. If you bought a painting for $20 and it's appreciated to $15,000, you're owed $15,000 when someone destroys it. If you bought a suit for $2,000 and it's more moth-hole than cloth and it's been through a few paintball fights, you're not owed $2,000 when someone destroys it.

There’s an easy solution: the airline automatically owes the maximum amount. This would save everyone much time and put some burden back with the airliner (by potentially paying more than the customer had, though at around USD 1800 it should be quite even, especially once you consider the time spent to get your money back)

You already need to insure higher values anyway if you want to be entitled to a reimbursement, so this would set a nice minimum that encourages customer friendly behavior.