1) The Simpsons
There’s no denying that The Simpsons in the 1990s was one of the most significant and timeless shows in TV history. If it had finished around the turn of the millennium, it would have preserved the amazingly high hit ratio of the show. Unfortunately, The Simpsons is still going sixteen years later and it jumped the shark many years back.
Unlike previously mentioned series, there wasn’t really one big decision that caused a downturn in the series’ fortunes. Rather, it was just the show’s ridiculously long life span that dulled the sharp wit and heart of the first few seasons.
Thankfully, the heights of its early years are still enough to keep the show fondly thought of by most people. Still, the series is a poor imitation of itself nowadays and has undoubtedly lasted far longer than it should have done.