Fox's critically-acclaimed musical series Glee became a massive hit when it debuted, so why wasn't a potential seventh season didn't happen?

Here's why Glee didn't continue with season 7. The brainchild of frequent collaborators Ryan Murphy and Brad Falchuk, as well as Ian Brennan, the show revolved around William McKinley High School's glee club and its members. Debuting in 2009 and running for six years until it ended in 2015, it launched its main cast members such as Lea Michelle, Diana Agron, Naya Rivera, Cory Monteith, and Chris Colfer among others to mainstream popularity.

Glee was an instant hit when it premiered; the critics gave it generally positive reviews, but the public immediately got hooked on the series with over 10 million viewers tuning in when it debuted. Aside from the plethora of characters — each one presented in a relatable way, not to mention the high school drama that has always been a popular narrative trope, the series' choice of music also played a big part in its success. Songs covered in Glee were released officially. In the end, the show also racked up more than 36 million digital single sales coupled with 11 million albums sold around the globe.

Fox continued to milk Glee's success with live concert tours, followed by a 3D concert film titled  Glee: The3D Concert Movie. All was going well with the show as it also continued to attract big-name celebrity guest stars such as Gwyneth Paltrow, Carol Burnett, Helen Mirren, Jeff Goldblum, Idina Menzel, John Stamos, Neil Patrick Harris, and Ricky Martin to name some. The series ultimately wasn't able to sustain people's interest, but that's not the only reason why Fox wrapped up Glee after six seasons as there are a couple of other factors that contributed to the show ending.

After two years of massive popularity, Glee's ratings dropped significantly in season 3 — with the series reportedly losing nearly a quarter of its viewers. That trend continued for the next few years with the show unable to recapture the public's curiosity after its first couple of seasons. This steady decline can be chalked up to a few reasons. Firstly, the show started limiting guest star appearances - like Britney Spears' cameo - which had previously boosted people's interest in the series as each high profile celebrity was guaranteed a performance — something that piqued the interest of casual fans who may not be familiar with these artists' ability to carry a tune or dance. Secondly, Glee's original premise also backfired.

When the show began, the intention was for the series to focus on McKinley High's glee club — not its members. The series was supposed to have a changing roster as the older students graduate and move on with college but viewers became too invested in its core cast. While Glee attempted to introduce new members, but the public was still more interested in their predecessors; this forced them to stretch out their storylines past their high school stints. The sudden death of Cory Monteith, who plays Finn, the school's quarterback and glee club member played a part in Glee not pushing forward with season 7. The actor tragically passed after he overdosed with a mix of heroin and alcohol. After the season 5, episode 3 tribute episode titled "The Quarterback" aired, Murphy revealed that the show's upcoming year would be its last.

Fans who stuck with the show until the very end were understandably sad to see the show not continuing past season 6. That said, Glee was still lucky few to have the opportunity to craft a fitting send-off to its characters instead of ending it abruptly with a string of lingering plot holes. At this point, there are no plans for a reboot, but with a lot of  old TV series getting revived, it won't be surprising if the musical series comes back on the air.

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