Did you check the voltage rating on that new cap before you put it in? I read on a radio repair forum that the old caps were often rated way too low for today's line voltage, which runs a bit higher than it did back in the 60s. That extra push is usually what kills them early, so going up a step or two on the voltage rating can add years to the new one. Heat is the other big thing, and tube radios get plenty warm inside that cabinet. If you used a cap with the same or higher voltage and it sits away from the hot tubes, it should last a good long while. Mine has been going strong for about three years now with no hum at all.

Oh man, hate to burst your bubble but that's not really a "found a hidden gem" thing, it's more of a chain-wide deal. Stores like Wegmans and some others have been selling "misfit" produce for years because shoppers won't buy weird-looking veggies even though they taste the same. If you're near a bigger grocery chain, check their produce section next time, you might see the same bin at home.