I'm not so sure about this. All those not-so-subtle slights to his masculinity: has no rhythm, can't fix the truck, wouldn't listen to her if he were going deaf, never will make as much money as she made at Neiman Marcus (!) add up to something. And her gabbiness seems the equivalent of Lureen's bleached hair, an outward sign of inner frustration. I think she probably understands approximately as much as Lureen does, at this point.
Does LaShawn say Randall will never make as much money as she
made at Neiman Marcus or as much as she
spent at Neiman Marcus?
A minor point, to be sure, but, with respect, I think it's the latter. She says she could have had any job she wanted in North Dallas but she took Neiman Marcus because, Honey, when it comes to clothes she's got no resistance.
I don't think LaShawn is frustrated. I think she's just an airhead. But, in her own cheerful, oblivious, ditzy way, I love LaShawn!