For those not familiar with high volume production you would be amazed at what can cause serious disruptions. With something as complex as a pinball machine the BOM must be horrendous to manage. All it takes is for one supplier to have an issue and the whole thing grinds to a halt.
It could be something as mundane as a container ship full of screws being held in a dock or something serious like a bad batch of clearcoat.
The main thing is that if it is a quality issue they get it sorted before the ship. Better right and late than wrong and on time.

I do agree that better communication from Stern would be desirable though.

Hobbit serial no. #0001 and Hobbit serial no. #0002.

I can understand the delay in getting WOZ to the market but the delay in The Hobbit is poor. What's worse is that they have released it (very late) and the code isn't totally polished. You would have thought that the code would have been spot on due to the delays.
I think for their future (and I really hope they do well) they need to learn to get their product to market faster.

You may well have dodged a bullet with the current playfield issues. Buy a decent, used machine and wait for Stern to sort themselves out. Then you can sell the game you bought and buy NIB when they have ironed out the problems.