I get the sense you're saying this tongue-in-cheek, which, fine, I get it, I love me some Diet Pepsi too and consider it a workday essential. But just buy a couple six packs on your day off - which you can do because you won't be running the place from afar on weekends because you're not taking their phone calls when you're not on call anymore, right? Same with your candy of choice. It'll save you money and you can stress about important stuff instead running out of snacks!
Also, please, I'm begging you, drink some water. Like I said, I love my diet sodas, but there is nothing like cold water when you've been running around crazy in isolation gear all day. If you hate it plain, get those little flavor powder things. Nourishment is not primarily about what tastes good. Especially at work, we need to eat and drink to fuel ourselves through the shift; it doesn't have to be delicious. You need to drink some water at work.
To answer your question, no, I have never witnessed regular competition at the vending machine, in any place I've worked. Some people always buy lunch and snacks at work, some religiously pack food, and the rest of us switch it up. There is always plenty of food and beverages, and no one takes the entire stash of everything in one go.
For my favorite food options for work, I am trying to be better about bringing lunch due to the expense, and I'm having some decent success. My boyfriend and I make two or three meals each week and I bring the leftovers; it's always something easy to reheat and has at least some veggies and protein so I feel like I'm doing something good for myself. I also bring *one* 20 oz Diet Pepsi, which I'll drink when I eat lunch mid-day, and my reusable water bottle as beverages, and toss a small amount of my dessert craving of the week in my bag. Sometimes it's those Keebler rainbow cookies because sometimes you just need a childhood favorite; sometimes a couple fun-size candy bars; whatever.
All this to say - grocery stores, a little light meal planning, and some reasonable boundaries with yourself are good things!