No kidding, it's like when new writers come to a show and the main characters are married and they are: "We don't know how to write married couples, so let's give them drama or try to break them up so we can write them easier." It makes them come off as morons in the sake of not admitting their own limitations in writing. It was like how Wilson was written as time marched on. He went from the man who traveled the world, taught many students and then he didn't know how to work a telephone. Sorry, that wasn't funny, it's like he lived under a rock.
Another odd thing was outside working at the pet store. Marty doing construction side jobs and also working for a zoo. These aren't just fly by night businesses. It's hard to work at a zoo, especially when it comes to animal care. People who did work there were being paid close to $15 an hour in the late 90s and the other odd jobs Marty was working would have been under the table or little taxes. So, really Marty would have been making some money, plus if he was switching jobs that many times or quitting. That would have raised red flags to the point he would have been lucky to get a job at a drive through at McDonald's. There is the sake for a joke, and then there is a man with a piss pour attitude on work and life that is causing all the problems himself.
Though I did question, what was Nancy doing for a living? Even when Marty was working as a charter accountant, he would been making a good money. However, once the girls were in school, why would Nancy stay at home with the girls? Plus, she knew Marty wasn't making much after she kicked him out. I doubt any lawyer would have said: "Yeah, you have to pay X amount in alimony." Nancy would have laughed and gone: "What money?" It was like Alan's divorce on Two and a Half Men, no one really understood how divorces work, just it was a good for a cheap laugh.