Most of the ones that were going to have the major failure have already self-destructed and are out of circulation that's probably why you haven't seen them.Personally I have never a major failure of the Courage single though I have heard of them thru the grape vine. It is called a bucket engine for a reason as the crankcase is like a bucket.
Most times when lower crank seals go bad it is the lip next to crankshaft. While just sitting there oil runs down the crankshaft onto the motion drive pulley. Then when you crank up the engine oil is slung off that pulley. The engine's crankcase will be dry as oil does run uphill or spray uphill unless forced to do so.
Also when new seals are installed it is possible to roll the lip and have the gather spring to become dislodge causing leaks. Now on rarer occasions the seals can leak between itself and crankcase. But you are dealing with a seal that is 15 yrs old so I think as harden over the years on top of wearing normally. It is the reason I keep these seals in stock here.
Also you hadn't already disassemble the engine you could have used UV dye to find the leak down before doing an invasive disassembly. It can save a lot of unnecessary work.
These things kind of go in cycles.
It also has to do with the region they're in which affects people's mowing habits and the season.
I was tracking them quite well for a while and it seems that all the 2000 to 2003 models have already blown up. Lol
I thought anything 2006 or newer was out of the woods but I finally found two 2006s that had the bolts not tight enough but still not as bad as the old ones.
To this day I have never seen anything 2007 or above where the bolts weren't nice and tight.
It was just those front five also. And of course there's only two where the flywheel can hit and cause the crack but even before that those front four to five will loosen up and the whole cover will start to walk around and open up the guide pin hole and everything else.
If you catch it even at that point, you can clean all the threads out nicely and use at least blue loctite on them and preferably a lock washer or some kind of shoulder bolt that's a locking bolt along with loctite and torque them to the factory spec and it shouldn't happen again.
I still check everyone that comes in but I can pretty much guarantee that if it's 2007 or above they're going to be fine.