Very good question! Luckily, today we find more examples in the media where traditional roles are challenged. There's nothing inherently wrong with maintaining different gender expectations, but it's important that people not get too boxed in by them. This commercial's comedic value is an example of that. Let's break the commercial down into parts:
- First, you've got the guy doing his yard-work. This is a typical male role. He looks hot and sweaty like he's been doing "man's work." He's a rugged looking fella with a bit of "5 O'clock shadow."
- We see that he sees something over the hedge by the pool. There are hands putting down food and "girly" drinks with little umbrellas in them. The insinuation is that they are women out by their pool. The man's reaction indicates some state of "male drooling" over what he's seeing. This phase, in itself, is a stereotype...the idea of the "landscaper" who comes across beautiful women out by the pool who then entice him to come over and join them. The drink with the umbrella is another stereotype. Men don't typically drink in this fashion.
- He is visibly excited by what he is seeing. Stereotypically, he is making all kinds of faces and mouthing words in an effort to appear attractive. His "lust" has made him forget about his work.
- This is where the roles are challenged...we are shown that the "women" are actually two men. Of course, Tom has been ogling the bag of chips all along, but that's irrelevant. The two men have been given the role, by the commercial, as the assumed object of desire by the pool that would have normally been filled by a model of some stripe. This flips the scenario on its had.
- Fulfilling her typical role, Tom's wife appears with a drink for her husband. This is a commonly portrayed role for women.
So the commercial challenges stereotypes by surreptitiously placing two men in a role that would typically be reserved for women. The rest (the man doing yard work, his wife bringing a drink) are pretty gender stereotyped. It's not a REAL challenge, though, because although one was pulled over on the eyes of the viewer we know that TOM was not interested in the men but rather the bag of chips. Had he been interested in the men, that would have been an actual challenge.