Legitimate question

Things change in 20 years. Baywatch was also hugely successful. And look at that pile of *beep* now.
I think the premise of 3rd Rock allows for a lot of far fetched stretching of imagination. I feel like I'm dating myself, but it was always a highlight of our evening for me and my sisters and mom to sit down and watch it.
I think the cast had some great chemistry and the jokes were well written.

Of course it's a "legitimate question"-- who would argue otherwise?

That said, I don't have a legitimate answer. I do remember that the show was heavily promoted by NBC during the premiere and for at least the next few seasons-- Super Bowl tie-ins, an "experimental" 3D episode, the works.

Also, the premise was hyped as something more than, say, "My Favorite Martian" 2.0; it was touted as both a zany comedy and a sharp and insightful social satire (as sitcoms go).

I sort of remember some "water cooler" buzz from people who liked it because it was "different" and "out there" in a good way; it had a mix of standard broad sitcom humor and witty observations about life on Earth (and life in academia).

And I think it's possible that "3rd Rock" may have gotten some traction because of the success of "ALF", even though it premiered several years after "ALF" was cancelled.

Like I say, it's a circular answer. But I think it really was a matter of a heavily promoted "fresh" concept with an appealing cast just catching on.

Great premise.
Great cast.
Great writers.

At least for a few seasons, then it was able to coast.

The NBC network took a chance. After the fact, one can say it had a great premise, great writing, yadda, yadda (and it did), but this was surprise hit to everyone involved. It took almost 2 years to get on the air and ABC passed on it twice.

That's when NBC picked it up and put it on the schedule as a mid-season replacement. But it was their only mid-season show and they felt confident it had a chance against other sitcoms -- which at the time were all Seinfeld and Friends knock-offs about dating and life in the city -- so they poured a $20 million advertising campaign behind it.

The show enjoyed an ideal combination of elements that made it successful: Great support by NBC; unexpected premise; surprising casting (John Lithgow was not known to mainstream America as a comedic actor); a choice time slot that allowed it to build its own audience rather than just coast off a lead-in (it was on Tuesdays between a dying Wings and a strong Frasier); and tight writing. That's why it was a hit. But without this mix, it could've easily failed.

Friends,

I believe that this could partly have been due to the BBC series, "Red Dwarf". RD was an instant hit with US fans, and had recently resumed after an imposed hiatus due to one of the stars being tried on trumped up charges. The Brits had a hit on their hands, so why not try it here? And the two American made pilots for Red Dwarf did not go over well with test audiences (of course), so something completely new had to be tried. Whatever, it worked. I did not watch 3rd Rock on it's original run, catching only a few episodes simply by channel-hopping. But in less than 48 hours, I've knocked out the 1st season and I'm about 10 episodes through the 2nd season on NETFLIX. It's not very often that American television does something so right, but they nailed the target with this one. The cast is phenomenal. I recall that John Lithgow received at least one Emmy for lead actor in a comedy, and he certainly deserved it. It was Lithgow and Curtin that gave this mass appeal. Two stars doing what they do best, and making it look effortless: comedy. "Dying is easy, comedy is hard." -Speaker unknown.

CKB

Season 1 was reasonably successful because it was very humorous and the character acting was top notch out of the gate. It rated 22nd in the Nielsen ratings in its first season. Season 2 slipped slightly in ratings to 28th. Subsequent seasons continued to fall more as each season passed until it was called to be canceled in its 6th season while at 89th in ratings. The end was written and broadcast in its final season. Not many people realize it was canceled because the 6th season was a complete 20 episodes - just as many as the first season.

In the big picture, it was not a greatly successful series. It was rather unique on the other hand and many people love(d) it.

John Lithgow played a villian his entire career and this show proved how great an actor he was. Similar to Christopher Walken's career.

Additionally, it was a great twist on a fish out of water.

Also, Jane Curtis and Lithgow were movie actors. It was unheard of (career killer) to make the switch to TV.

Jokes were non stop and the supporting cast knew their roles.

I don't don't watch too many sitcoms, because I can't stand the precocious children who are smarter than the adults. But I found this on Netflix and I love it.