I read all the various post with respect to damaged or broken engines here. This is a small vocal group as compared to the folks that run and buy trains. Granted this is the dedicated hobbyist here.
I just can't see how from a statistical perspective a person can state with certainty there are issues. Go sit in your LHS and ask every customer that comes in if they are on this forum. I think you might be surprised how many are not. So is this forum a statistical representation?
I think only the manufactures know, and it does cost them to do these repairs under warranty, so I do think they are vested in quality. But price point matters too.
This is still small volume. Larger the volume sold, more profit with ability to hire best manufactures and focus and pay more for quality.
Not that there isn't low cost ways to improve, but considering how many time Lionel approach bankruptcy, and who knows what the profit margin is for other train companies, there doesn't seem to be a lot of money room to approach a higher level of quality.
Statistically, sooner or later some one does has bad luck and does get several lemons in a row; while some one else doesn't have any issues. You can see it in these post. G