It's a sit-com that tries to sell itself as cynical realism, so I think 'Not realistic' is a fair criticism. I think the worst episodes in the series are the least realistic ones. Like, the one where Michael promised to pay for all those kids' college educations is easily the worst of series, IMO.
But I do like the way they're writing the Jim-Pam storyline. It's always been clear in Jim's character: He hates his job and the only reason he didn't quit a long time ago is he loves hanging out with Pam. So it makes total sense that he would hop at the chance for a more exciting job he's passionate about. And I don't think the ending of that episode means the end of their relationship problems. The ending of that episode was both of them seeing their marriage slip away from them and fighting not to let it go. Some of the tension was released but they're still in the same position: He started a business in Philadelphia and she doesn't want to go there.
But it is true, the storyline is explicitly designed to be audience-torture, and it's not funny.