There is a behavioral literature on what's called 'stimulus equivalence' - it shows how emergent, novel behavior evolves out of training the underlying relations (e.g., train a>b and b>c, then you get the emergent c>a). This happens with humans down to the level of mild retardation, but it's very hard to demonstrate it in animals.
Such emergent behavior is a kind of variability - the same genotypic variability that the environment 'selects' from to reinforce complex stimulus-governed learning.
If animals show observation learning, as you suggest, it's a mistake to conclude that it's not learned. As dozens of studies have shown, when the reinforcement is contingent, not of a fixed behavior, but on a conceptual behavior, that's what's learned (eg. an animal doesn't get food unless the sequence of three behaviors on a 3x3 grid are totally unique relative to the last 100 responses). Such contingencies are natural in all animal environments.
An animal or person can't execute complete motor performances according to some computational scheme, unless by this you just mean neural-networks (which don't compute, they just respond). If you look at primitive reflexive responses in insects, you see that the underlying neural pathways are, at the micro level, different for each individual. In other words, the brain develops according to environmental feedback (the first matrix movie has much to teach us about this). This is not learning, but the same notion applies to learning: a four legged animal has to learn to walk, then run, and gallop, and that neuronal-based learning is governed by feedback between the organism and the environment. You don't have to call this operant conditioning, but that's all that's involved: a complex biological system adapting from environmental feedback.
We overlook the power of conditioning because we think in simple terms of behavior being reinforced. As noted here -- https://psycnet.apa.org/record/2000-08385-002 -- behavior is not what's reinforced. What is selected is a stimulus-response relationship. Think of memory. Memories are not stored, if they were, the brain would have to remember where they were stored, ad infinitum. Memory is just a tendency to respond based on history: we see a movie, we remember a movie. It's all about remembering (a kind of behavior), and you won't think of what was the first car you owned if you don't read this sentence. Without stimuli, including interior/private thoughts, memories don't really exist. Sensory deprivation shows this impact of removing stimuli.
A problem with Skinner was he often simplified things too much. But not always. As seen here -- https://www.jstor.org/stable/27759371 -- his offering of a 'selectionist' model where the operant was the constructed product of cultural conditioning, anticipated a number of influential philosophers that few would think to tie to Skinner. As well as a number of post-modern philosphers