Animal sanctuaries, national parks and legally protected wetlands and forests are of course ideal for animals, there are national parks allover the world, Africa, Asia, Australia, everywhere and are probably the best way of fulfilling all the objectives.
But just how many people could afford to visit those parks? People with money can easily fly to South Africa, or Kenya, for their wildlife safaris and adventures to watch the animals up and close in their natural habitat, and then post their pics on Instagram and FB as much as they like, but what about poorer families living in poorer countries? how exactly will they enjoy seeing and interacting with all those weird and wonderful animals? Going to Zoo is still a relatively cheap family entertainment for a whole social class that has no means of accessing the more exotic and naturally expansive facilities spread over hundreds of acres in different parts of the world.
You could argue for bringing in more regulation surrounding the zoo industry, bringing in a cultural change into how animals are treated and nurtured in such controlled facilities, talk about closing down zoos that fail to adhere to guidelines and expected standards, but advocating for a total ban on zoo industry (and terminating employment of thousands of workers associated with it) is surely over the top rhetoric. We have not managed to ban tobacco industry over all these years that is responsible for deaths of millions of people, coz it brings in billions of dollars in tax revenue vital for many public services, and here we are hell bent on banning zoos? it does not make much sense to me.
If all zoos are closed down today, then visiting and experiencing animals and the joy this brings to us the humans will only become exclusive to the rich and affluent who are able to afford their wildlife safaris and adventure trips to animal sanctuaries and national conservation parks.
Additionally, many animals can only be kept in open spaces if they are within their natural habitat, with the right climate, atmosphere, temperature weather and provision of food , prey and water. You cannot open expensively run and guarded natural parks in places and continents totally different from the natural habitat of a given animal, for example, you cannot place a Siberian, or even a Bengal Tiger at the Serengeti National Park in Tanzania, it will just not survive there. However in properly run zoos at a much smaller scale, provisions and efforts can be made to make life easy for all sorts of animals from different and varying habitats allover the world as they can be kept inside specialised enclosures specifically designed to mimic their natural habitats as much as possible.