What should have happened was to have spared a small amount of grease on the shafts a long time ago. Now, it's press time.
Gauge wheels are expensive, as you well know. Just a little interim care goes a long way.
First off...I grease my equipment on schedule... Secondly, that wheel was 16+ years old and even at $200 with bushings, it didn't owe me anything... I mow 3 of my 6 A so this MMM earns it's keep...