True true..all other factors aside I can tell you if I were to price out what you had mine might cost less (except for grocery and sales tax mine may be higher). I shop at Aldi,
Walmart, and Costco as my main places and Costco now has more organic food choices than Whole Foods; I also buy generic most times but I pay very close attention to the packaging to see if I'm getting apples to apples or apples to oranges as far as nutritional value. When I lived near Hy-Vee (regional but very large chain of employee-owned grocery stores) I shopped there over all other grocery stores because their prices were lower but quality was still good.
And I certaintly can understand how it can get boring and old eating out at WDW day after day but because people spend different amounts/days in WDW that amount varies a lot too (I spend 5 non-consecutive days at WDW for example). I also take vacations for around the 7 or more days (this next trip we will be gone 10 days but 2 are travel days 3 are UO days and 5 are WDW days) so for me it's common to eat out for that many days in a row when I'm on vacation but like I mentioned before that in itself is a different variable since others may not do vacations like that.
As for your beer comment, while very true, WDW is no different than anywhere else in that regards. Some places in WDW are generally regarded as a better value for your money.