Most animals in zoos get bored of staying in the same area for their whole life. Also instead of making money off zoos they could make money off safari tours. The government can make a law that you can not hunt the animals living in "protected areas". Overall the animals would be happier living in the wild.
Sure, putting a few wild animals in zoos may be less comfortable for some of them but look at the big picture. Each year, about 50 million people go to a zoo each year. For many/most, this may be their only chance to actually see a wild animal in person. Sure, you can watch them on TV or look at pictures in a book but that pales in comparison to seeing them live. That is because going to the zoo costs very little and fits the budget of most families. What would happen if zoos did not exist? Obviously, most people would never get the chance to see them in person but others who have more money may turn to safaris. As air travel and tourism becomes more affordable, more and more people are already going on safaris each year. If we didn't have zoos, this number would skyrocket. Tho the animals are still in their wild habitat, they tend to avoid humans so when humans become more an more present, they move away. Just the added traffic has caused much of their natural habitat to be destroyed. What was once a watering hole for a herd is now an avoided area causing the entire herd to suffer.
What is worse, causing a tiny few to be held captive or possibly threatening entire species in the wild?