Yes, we could do that, but what would be the benefit? I'm saying that whether we want nature conserved and whether we want them to be in cages for us to look at are entirely separate issues that should be evaluated separately. The best argument in favour of zoos is assuming that the people who want to look at dancing bears would be sufficiently enraged by their absence that they would decide to condemn the whole of nature in not doing conservation.

As for why I think we could do it, the answer is because we obviously can. The world become a much worse place once you realise the many things of which humanity is capable, yet which we choose not to do.