Gilmore Girls was great throughout most of its run, but season 7 - the last prior to Netflix's revival, Gilmore Girls: A Year in the Life - saw the show take a major dip in quality, but there are some clear reasons as to why it was so bad. Created by Amy Sherman-Palladino, Gilmore Girls charted the lives of Lorelai (Lauren Graham) and Rory (Alexis Bledel) Gilmore in the little town of Stars Hollow, running from seven seasons on what was then The WB network.
While it wasn't a massive smash, the show did receive strong reviews and built up a loyal following, which was in part thanks to its mostly consistent quality. Season 7 was different though: the storylines were worse, the characters didn't seem quite right, and the iconic rapid-fire, pop-culture-referencing dialogue felt oddly stilted. Gilmore Girls had been known for its warmth and humor, operating as comfort blanket TV (but also much smarter than that label implies), and this wasn't the same show that fans had grown to love so dearly.
The main reason for Gilmore Girls season 7 being so bad lies in the merger of The WB and UPN, which resulted in The CW network being formed. That happened during production of Gilmore Girls' seventh season, and led to a major behind-the-scenes shake-up. Amy Sherman-Palladino and her husband, Daniel, had served as showrunners and writers throughout the series' run, but ended up leaving Gilmore Girls behind for season 7 because of a dispute with the network. The CW claimed this was over salary, while the Palladinos have said they needed more writers, a short hiatus, and an eighth season. Ultimately, they left the series, and while many staff writers were still around, the series wasn't the same. So many of Gilmore Girls' strengths - its dialogue, its theatricality, its character work - came from Amy Sherman-Palladino, whether as writer, director, or general overseer. Without her influence, Gilmore Girls just couldn't work as well as it once did.
Still, there were some talented writers, so that doesn't fully account for why season 7 was so bad. There's also the fact that so much of it was rushed through, where an eighth season would've helped things, and it made some very poor choices in terms of storylines and character developments. These included Lorelai and Christopher getting married, Lane getting pregnant, Logan proposing to Rory pretty much out of nowhere, and a whole lot of Rory/Mary/Logan related nonsense. There were some terrible decisions made in Gilmore Girls season 7, although they might've felt less so if Sherman-Palladino had still be onboard. After all, the series made missteps before (see: April Nardini), but it was still Gilmore Girls. That wasn't the case with season 7, which was lacking the dialogue, the heart, and the charm, along with a sense of who these characters really are.
When Sherman-Palladino returned for Gilmore Girls: A Year in the Life, she carried out much of what likely would've happened in the final seasons of Gilmore Girls had she stayed in charge: Luke and Lorelai get married, and Rory is pregnant, right down to the infamous final four words of Gilmore Girls. The Netflix revival wasn't perfect, but it was much better than season 7.