Money is a lagging indicator for product quality. When a company's built up a strong brand, it can take years (or sometimes decades - witness Sears and Applebees) of bad experiences or outdated products before it starts to show up in sales numbers. But when it does, it usually ends up cascading rapidly, oftentimes faster than the company can react.

Apple started its slide the first time around 1989 - that was when Mac models started proliferating, when System 6 came out, and when its first sales decline happened. Jobs didn't return until 1998. That's almost a decade in between.

It's similar for other dominant companies - the writing was on the wall for IBM when Compaq & Dell started selling PC clones in 1983/1984, but they didn't need a turnaround until 1993. Sun Microsystems hit its zenith at the top of the dot-com boom in 2000, but its stock price didn't start sliding until 2007 and it wasn't purchased until 2010.