A building does not actually enter a superposition when unobserved, nor does Schrodinger’s cat. The point of that metaphor was to demonstrate, through humor, the difference between quantum objects and non-quantum objects, by pointing out how ridiculous it would be to think a cat could enter a superposition like a particle. In fact, one of the great mysteries of physics right now is why only quantum objects have that property, and in order to figure that out we have to figure out what interaction “observation” actually is.
Additionally, we can observe the effects of waves quite clearly. We can observe how they interact with things, how they interfere with each other, etc. It is only attempting to view the particle itself that causes it to collapse and become a particle and not a wave. We can view, for instance, the interference pattern of photons of light, behaving like a wave. This proves that the wave is in fact real, because we can see the effects of it. It’s only if we try to observe the paths of the individual photons that the pattern changes. We didn’t make the photons real, we could already see they were real by their effects on reality. We just collapsed the function, forcing them to take a single path.