I see what you're doing, and you're completely correct. It's expensive to make meals solo.
But it's an uphill battle, and you won't win.
Nobody cares that buying new ingredients to make tacos for a party of 1 is expensive.
If they aren't doing it yet, they will soon be telling you that you aren't holding it right, wherein:
You should enjoy leftovers. You should embrace and cherish the idea that electing to have some tacos one night dictates your meal choices for the days that follow.
That extra chopped onion that is all stinky and sulfurous by day 2? The meat that isn't ever going to be remotely the same again? The tomatoes that are reverting to slime? All that extra lettuce? That fresh cilantro that doesn't have any other culinary use in your chosen diet? Buck up and eat it, or shut up.
People are broadly incapable of having non-disingenuous conversations about the cost of preparing fresh food in small quantities.
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Tacos for 2? Or 3? Or 8? Or 16! That's really easy and efficient to make for a one-time meal at home. It scales up very well, indeed. It's a great way to feed a bunch of people relatively inexpensively.
For a person cooking for themselves that isn't inclined to eat the same thing for multiple days in short succession, tacos get do kind of expensive -- expensive enough that buying them hot, fresh, and pre-made becomes very attractive.
(My personal favorite is when they tell me that I should try having different taste and just change my preference for the foods that I eat instead of complain about the price. Or when they tell me that I'm a very poor meal planner just because I want only one burrito: FFS.
Sometimes a burrito is just a burrito, and that's OK.)
> And most of these supplies and prep are going to last what, ~4 days before they spoil?
Rice lasts a very long time. Tortillas last a long time in the fridge (you can probably freeze them?). Freeze the meat. Beans last forever. Sour cream and cheese last a long time in the fridge and you'll certainly use them for other things.
Guacamole/avocados/other veggies are potentially harder to deal with for long term storage, but that depends and it looks like there are some options. Salsa also keeps for many, many months.
As far as time goes, if you're single, many of the ingredients could be cooked in a batch and then frozen, even as whole burritos.
You're expanding the scope to a much larger process and pattern of behavior that has to be undertaken and managed. Sure it's doable, and you can save a bunch of money that way. But as a one line throwaway comment it's still nonsense.
Also freezing things or letting them sit in the fridge for weeks tends to change the texture. A main point of a burrito shop is the fresh ingredients.
But you wouldn't be making a single burrito. You'd be making several over several days, and/or using the leftover ingredients for other meals.
Economic literacy is truly dead, isn't it? Good lord.
This is what you said: "Make your burrito or bowl at home, and it'll cost $4 or less"
That statement implies you can straightforwardly save by substituting that one meal with a made at home meal. The reality is much more complicated, as shown by your backpedaling to making several burritos and other meals.
I could just as easily lob that economic literacy jab right back at you. For example, perhaps OP has a burrito once a week, to break up the monotony of eating a home made sandwich every other day. That would be savvy, right?