E: Looks like "standard" dogs are 1/8 or 1/10 lb. (https://learnhotdogs.com/what-size-hot-dogs/)
Considering these are half the price, the hot dog is priced similarly. However, as you pointed out, IKEA is still missing the free drink. Personally, I'd prefer a single larger dog than two small ones in order to cut down on the bread.
The ikea hot dog kinda sucks tbh. And size-wise, I dont think 2 of them equal a costco hot dog anyway.
Now, their veggie dog? That goes way too hard. It comes with toppings like mustard, pickled cabbage, and crispy onions. 2-4 of those things will fill you up cheap. Don't sleep on it, and don't judge it by its looks.
I think they are calling out that while both are plant based, one is meant to emulate a hot dog and one is not. That middle one probably isn’t trying to be a hot dog, but its own thing.
Note the veggie dog looks like veggies and spices packed into a sausage shape, but with a texture that looks very different, that is the same size as the hot dog. The plant based dog looks like the hot dog in color and with a similar smooth looking texture.
The veggie dog reminds me of a brautworst, which is roughly the size of a hot dog, but with very different taste and texture.