You get hybrid vigour when you cross two lines that have been separate through many generations, such as two pure breeds. And no, you don't technically get a "hybrid" as such, but that is just a naming things. Hybrid in this context just mean the hybrid vigour, which is not limited to hybrids only.

What you do get is a boost to genetic diversity that improves the overall vitality in the offspring... including things like general health, growth, fertility, number of offsprings et.c.

Hybrid vigour is a proven thing, and much production breeding within animal industries rely on it consistently. E.g. grower pigs (the ones we eat) are usually crosses between 2-3 particular pig breeds. Their mothers are F1 crosses, and their fathers are either F1 crosses or pure breeds. Hybrid vigour is taken seriously in animal industries, because aspects like health, growth and vitality translates into profitability there

When you cross a poodle and labrador, you get a boost too. If the parents are crap dogs, the boost may not outweigh their flaws, but the offspring is still better off compared to if the two crap dogs mate with someone of their own breed.