Keith Urban, Ryan Seacrest, Jennifer Lopez, and Harry Connick Jr. (Michael Becker/Fox)

The once-scorching hot “American Idol” has been flailing in the ratings for a while, but it became embarrassingly evident this week — the first part of the Season 13 finale on Tuesday night attracted only 6.6 million viewers, the lowest-rated episode in the history of Fox’s reality singing competition. On Wednesday, only 10.1 million people watched 23-year-old rocker Caleb Johnson triumph as the winner over 17-year-old powerhouse singer Jena Irene; that’s by far the least-watched finale ever (down from last year’s 14.3 million).

Ouch. For comparison’s sake, the glory days of “Idol,” around 2006, regularly clocked an average of 30 million viewers; the most-watched episode was the Season 2 finale, in which 38 million people tuned in to see Ruben Studdard triumph over Clay Aiken.

Enough reminiscing about the good old days, it’s time to face facts. No matter how the producers have tried to reinvent the show (new judges! twists! feuding divas!), the numbers have drastically slipped over time, shedding viewers nearly every year since 2008. Logic would tell us that it’s time to stop trying to make “American Idol” happen — except that it’s already been renewed for Season 14, and, honestly, Fox could do a lot worse than 6.6 million viewers these days. (Sorry, fake Prince Harry.)

So, creators will reboot the show once again next year. Changes are in progress: Fox entertainment chairman Kevin Reilly told reporters recently that “Idol” will be trimmed from 50 hours to 37 hours over the season and will probably air once a week instead of twice. No word on the judges; various reports say that Harry Connick Jr., Keith Urban and Jennifer Lopez will return, but nothing official yet.

The new Connick Jr.-Urban-Lopez combination did seem to gel a lot better this season than previous judges tables — an attempt at a kinder, sweeter “Idol” this year — it obviously wasn’t enough to boost the numbers. None of the other changes over the past five years have, either.

Looking back, the “Idol” shake-ups really started with the first noticeable dip in viewers — in Season 7, an average of about 26.6 million people tune in, a drop from 30 million the previous year. Natural decline for an aging show. So going into Season 8 in summer 2008, producers decide to change the judging panel for the first time: Add songwriter Kara DioGuardi with Simon Cowell, Paula Abdul and Randy Jackson, injecting some more “girl power.” (Yep, that’s actually what creators said.) Paula does not appear pleased to share the spotlight, and it shows. The producers also add a “judge’s save,” hoping to add some more drama to the proceedings. Season 8: Averages 25 million viewers per episode, down 1.7 million from the previous season.

Obviously, that was the beginning of the end. As soon as the creators sign Kara to Season 9, the always-wacky Paula tweets that she is done. That throws the “Idol” universe into a bit of chaos as she’s the first judge to ever leave; producers sign Ellen DeGeneres to take her place. It does not go well; Ellen is obviously uncomfortable and relies mostly on scripted, unfunny lines. Plus, Cowell announces a few days before the season starts that this will be his last year. Season 9: Averages 22.3 million viewers per episode, down 2.6 million from the previous season.

Before Season 10, there’s an “Idol” bloodbath: Simon’s out, Ellen’s gone, and even Kara gets the boot. This is the show’s biggest reinvention to date, and it brings in Steven Tyler and  Lopez to shake up the panel with Jackson. The intrigue and Tyler’s weirdness is enough to boost the numbers a bit. Season 10: Averages 23 million viewers per episode, up 300,000 from the previous season.

Uh-oh: The mediocre Randy-Steven-J-Lo panel remains the same in Season 11, and the show takes the most drastic drop in viewers yet. Looks as if there’s no going back to the good old days. Season 11: Averages 17 million viewers per episode, down 5.9 million from last season.

Time for a Hail Mary in Season 12 — producers recruit pop diva Mariah Carey and rapper Nikki Minaj to sit alongside country star Keith Urban and the unstoppable Jackson. Mariah and Nikki hate each other, and reports of nasty fights surface before the season even starts. All that awkwardness on screen makes for an awful season, and the show really starts to sink. Season 12: Averages 13 million viewers per episode, down 4 million from the previous season.

Let’s start again: For Lucky Season 13, creators decide to make “Idol” a more friendly place, bringing in longtime “Idol” favorite mentor Connick Jr., along with the returning J-Lo. Keith, as a reward for sticking out the hellish last season, gets to stay on board as well. Things are steady for the delightful crew, but that doesn’t translate into more viewers, even when they try to add a scary twist with the “Hollywood or Home” bus. So far, this season has averaged about 10 million viewers. And we can only wait to see what they’ll dream up for Season 14.