I think another thing now that I have checked it out was that same fall A Different World premiered, which was also about college so they didn't want to have 2 shows on that were the same. I didn't remember when World premiered, I thought it was fall of 1988, but checking again, it premiered in the fall of 1987, so maybe that was another reason GAB didn't come back as well after all.

Yes, that is correct. Heard an interview from Lara (Sam) and she did say that was what was planned, which is why they had that two part episode in the 6th season where Nell goes to Sam's college and interferes with things. However, A Different World came along and maybe they thought that was better, since it was a spin off and not trying to reformat a show a third time.

True, the late 70's and early 80's, when Fred Silverman was president of NBC was a very bad time for the network, with a lot of shows that bombed and Silverman squandering all this dough on programming that he thought would turn it all around, which it didn't. Silverman was fired in June 1981, before this show went on the air, but it was obviously developed during his reign, since pilots are done the year before.
I guess the show did well enough to stay on the air, plus Grant Tinker, who took over, was more patient in giving shows a chance to get somewhere.

I seriously doubt it. That 1986-87 season was wretched, and I can't imagine that they would go with that premise either.
Gimme a Break like Facts of Life was born out of a time when NBC was struggling in prime time, and was renewed because it was one of the very few shows they had that generated some interest during its low point.
By 1987, NBC had rebounded spectacularly. They now had Cosby, they had Cheers, they had LA Law, they had Family Ties, they had the Golden Girls, they had Hunter. No way was Gimme a Break coming back, especially not after the last two miserable seasons. They were lucky to get the 86-87 season.

I've caught it. In fact, as I type this, am listening to it again on youtube. Not all of it is correct though.

I'd love to see that at some point.

On True Hollywood Story I heard that they changed the show because the idea of Nell still being a nanny/mammy type character was dated because they had a doctor and lawyer on the Cosby Show. Of course this didn't work but as the years went by there was no Chief or 3 daughters to look after. If they stayed in Glenlawn it would've been Nell, Joey and Grandpa living in that big house with the daughters "visiting" when they felt like it but it wouldn't be the same and still sucked either way. The show just ran its course.
But not tonight

I have no idea. I know that after the fifth season, the show wasn't doing well in the ratings and they tried to make changes to keep the show going, like:

1. Katie moved to San Francisco to be a buyer.
2. Julie, Jonathan, and their newborn daughter (who should've been named after her late grandfather) moved to their own apartment near campus.
3. Sam attended college in NJ.
4. Addy moved to NY to accept a job.
5. Nell decided to join her ass in NY so she moved with Joey and Grandpa to a NYC apartment.
   Of course, that didn't work because that changed the template of the show.

That premise was called "The Facts of Life" and starred Charlotte Rae as the dietitian/house mother.