I think because you asked the question, you know what the "right thing to do is" and you'll end up doing it.
When it comes right down to it, YOU are the one who has to make this decision. I can tell you, if you buy the ticket, you'll feel fine about it, if you don't buy it, you'll worry and feel quilty.
There are many ways to save $$, to not buy the ticket isn't the way to do it.
Also, you can feel better about buying that ticket, because (as someone else mentioned) there's so much more to the parks than the rides for the 40" and over crowd. My 3 1/2 DS LOVED his WDW experience and we definitely go our money's worth.
Lastly, I didn't see anywhere that "adults buying kids meals, adults splitting meals, sneaking in food and drinks to the park, are all against Disney rules." Come on, food is not sold "per person" except at buffets (and then it would be wrong not to pay for everyone)!
Oh well. That's my opinion on the matter. Hope it helps you.