Not wanting to be doom and gloom but I do think that within the next 3 to 5 years many Zoos will be forced to close leaving the way for super Zoos. The general public expect more glitz and show biz that the majority of small Zoos cannot or do not want to afford. Make the most of what's out there everyone it won't last in my opinion.
Got to disagree with your perspective on this I'm afraid.
Whilst the odd smaller zoo has problems, most have found their own path to facilitating continued operations and seem to be based on an even keel financially.
To be honest I think it's the medium collections that face bigger challenges moving forward as, unlike the smaller collections which people accept as they are (often making allowances for their size/situation), they face more pressures to continually change/improve. That said I'm sure they'll pretty much all rise to the challenge, after all they seem to have done so over the last couple of decades -very few significant zoo failures/closures.
Finally, I'd be careful guessing/asserting that the general public want more glitz -some might, but others are equally charmed by collections that are either small, quirky, local or perhaps more small child-friendly collections. For instance in Germany and the Netherlands there are a fair number of what you might term "super zoos" but there's also a large amount of smaller zoos that seem to have no problems attracting visitors to survive.
Pathetically attempting to make this post a little more "on thread" I'd point out that Twycross' historically impressive visitor numbers seem more to do with being a local zoo, with little competition, which many seemingly fairly undiscerning members of the local public have a huge amount of affection for (rather than it being any kind of "great zoo" over the last decade).