I watched that episode with some friends while still in high school. It was pretty funny, also given that Winkler was playing a guy who was my age - at the time - but still looked like my dad. We all knew it was a parody, regardless. On to the appropriate current metaphor, tho' - "jump the shark" isn't the right one in that vein. Given that that particular Happy Days episode had over 30 million viewers, the show didn't tank after that (although there were maybe 5 stations in the US at the time...), and Happy Days didn't suck for at least a few years after that episode - contrary to what Jon Hein might say about that series (and the other 200 others he pegged besides Happy Days, before selling out to TV Guide's owners for million$$$...).
OS X is a series of "sequels" - in project managers, CEOs, and focus - and, by that nature, it would have "nuked the fridge" and not "jumped the shark".
I have a friend who gripes about OS X appearance. I tell him to STHU and start coding, and that shuts him up...
All respect to a Tennessean, of course!