I think we need to change the housing system for many cats (and some other carnivors), which walk long distances: Longer corridors connecting several smaller enclosures.
I read an interesting study on tigers: They were observed in different zoos for 6h a day. They all walked many kilometers in that time regardless of the enclosure size - the smaller the enclosure the more pacing. Males more than females.
Even in enclosures with 4,000m² per animal, a considerable proportion of the movement was still pacing. Only in the zoo with the largest enclosure (a total of 35,000m² for four adults) was there (nearly) no stereotypy.
Very few zoos have that much space, but with corridors, you can greatly extend the walking distances even with little space. Many zoos that have such corridors also elevate them so that parts of the area underneath can still be used. And this is also an attraction for visitors. So a win-win-win situation.
