Based on looks, I could more understand Brenda Vaccaro playing Jill Taylor's mom than Polly Holliday.
Brenda V. and Pat R. look more alike.
Does anyone else see my point?

I just googled Brenda Vaccaro and I see the resemblance. I did like Polly Holliday in the role, although I didn't even recognize her.

To me, the lady who played Jill's sister Linda looked just like the lady who plays Jill.

God bless you and them always!!!

Holly

I liked Polly Holliday, but Brenda Vaccaro would have fit for the resemblance alone.
Jill being established as a native Texan, Polly Holliday herself being Southern made her a good choice. That said, nobody in the cast outside Tim Allen sounded anything like a Michigander. Dolores and Benny's New York accents in particular were very much out of place, and Brenda Vaccaro would have added another.