Yep, she’s gay. And yep, it wound up having an impact on her sitcom’s fate. After Ellen DeGeneres came out on the cover of Time magazine, and then had her small-screen alter ego do same toward the end of Season 4, ratings for the ABC sitcom fell 26 percent, dropping it from No. 30 to No. 42 in the rankings.

Creatively, the comedy garnered criticism — including from GLAAD media director Chaz Bono — for adopting way too serious a tone, to a degree that it disenfranchised even LGBT viewers. ABC cancelled "Ellen" in May 1998, after five seasons.

https://tvline.com/gallery/tv-shows-cancelled-for-dumb-reasons/#!6/dumb-tv-cancellations-ellen/

I was in junior high when she came out, and everybody was talking about it, both in school and in life. My mother was a fan of the show so I had seen it with her at times. If I recall, after the character came out, nearly every joke was a lesbian joke, and it got old, fast. Other viewers probably thought the same, and the ratings plummeted.

For what it's worth, Ellen DeGeneres herself, has pretty much insinuated (https://www.buzzfeed.com/joshuagmoradel/1998-interview-ellen-degeneres-bob-iger-homophobia-primetime) her belief that the show (https://www.latimes.com/archives/la-xpm-1998-apr-24-fi-42414-story.html) was canceled (https://tv.avclub.com/the-episode-that-liberated-then-destroyed-ellen-1798239919) due to homophobia. While I don't necessarily disagree that homophobia may have played some factor, we still have to keep in mind that the show was never a ratings (https://en.wikipedia.org/wiki/Ellen_(TV_series)#Ratings) a juggernaut to begin with. The coming out (https://money.cnn.com/1998/04/24/bizbuzz/ellen/) episode was far and away the high point (https://www.nytimes.com/1998/04/25/arts/abc-is-canceling-ellen.html) viewership wise.

The show went from 21 million viewers in Season 2 to 16 million in Season 3, stayed at 16 million average in Season 4 (which was buoyed up by what was at the time one of the most hyped sitcom episodes ever) and then dropped to 12 million in Season 5. The show was bleeding viewers until they had a brief moment of highly hyped publicity, and then continued to trend downwards after it was over.

Meanwhile, a lot of the writers for the show said it was cancelled mainly due to the show never really finding a solid (https://thewritelife61.com/tag/arye-gross/) premise and tone, and the ratings really did not justify a renewal at that point. Besides changing its cast a lot, the show as I just said, kept changing the whole premise of the show a lot through its five season run. It went from being about a woman who worked at a bookstore, to someone who owned the bookstore, to her going from being a single woman looking for a guy to an open lesbian. And towards the end, she was living with a roommate named Adam, which resulted in them having a fight, him leaving the cast, and then her hanging out with a new main character, a cousin of hers played by Jeremy Piven, who just moved into town.

The show wasn't even called Ellen (http://reviewingeverytvshowiown.blogspot.com/search/label/Ellen) at first (https://variety.com/1994/film/reviews/these-friends-of-mine-2-1200436106/), it was called These Friends of Mine (http://www.poobala.com/ellenandthese.html).