They had no job security at all, and the only family they had in Lanford was Jackie. So I wonder why they didn't just apply for regular jobs with regular companies, where they could have had health coverage, sick leave, and retirement plans?
They both had transportation. Why not commute to jobs in Chicago or some other place that had more industry than Lanford apparently had?
Dan was a skilled drywall/construction worker and mechanic, and Roseanne had a good work ethic too, despite personality clashes (and a lot of that was due to knowing she didn't have job security).
So instead of taking casual jobs why didn't they either pack up the kids and move, or commute to jobs with employers where they would have had security and some benefits?
Jackie could have done the same thing.
I realize all the insecure and temp jobs helped move the story line, but it seems kind of unrealistic as a plot device when they could have had permanent jobs and still been hard-working working-class parents.

I've always wondered this too but then I came to realize it all comes down to plot: they had to maintain the status quo to keep it relevant to working class people. Sometimes sitcom logic doesn't apply to real life.

Also, it seemed like Roseanne never liked any of her jobs and actually flaunted the fact that she was bad at them.

I guess it was not in her character's DNA to ever bother getting an education or even a better job, which would be the logical and smart thing to do (or at least you think), but that wasn't the case.