Chiming in that when I was writing about TVs for over a decade, trying to determine reliability was nearly impossible. Certain brands would have more reports of failures that I saw, but those brands also sold more than the other brands. And they were more often bought from a warehouse or online and not from a local dealer, so you might have a harder time getting it repaired or fixed than other brands which would lead you to be more likely to complain online about it. The best reference we had was an annual Consumer Reports survey of brand reliability from their readers, but the statistical deviation on that was +/- 4% almost I believe, so virtually every company was statistically the same in most cases.
So yes, I'm sure people are aware of cases where the LS50W has failed, and people for whom it has failed are probably very vocal about it, but it's also going to be nearly impossible to find reliable data on if the speaker has an issue unless you actually work for KEF and have access to that data.