I read a lot of news articles about world's fairs -- both past ones as well as proposed ones. Many of these articles feature comments afterwards. I think I've discovered an interesting pattern, at least in the United States and Canada.
In articles about past world's fairs, people lament that we don't have events like those anymore -- ones that bring a community together with a shared purpose and to celebrate. Oftentimes, people will mistakenly says something along the lines of "It's a shame they don't have world's fairs anymore." Sometimes you'll get the sentiment that people had more vision in the past and that we should be grateful for what was left behind.
In articles about proposed future world's fairs, comments tend to concentrate on the cost of the events: how we can't afford to have these events or that it would end badly with cost overruns and the like. Sometimes, oddly, they talk about how we should concentrate on creating infrastructure instead -- forgetting (or not realizing) that world's fairs are a good way to create civic buildings, transportation options, or even totally new communities.
How does this add up in my mind? Well, I'm still trying to figure it out, but we seem to think that we can no longer do what our predecessors did. We don't seem to think that it's appropriate to dream about possibilities in our communities.
In some ways, we think that dreaming is for "other countries" now. If we really believe that, then sadly, it will become true.
So, what can we do about it? We need to get more people to understand how we benefit, every day, from these events in the past -- not just physical infrastructure, but also world's fairs' immaterial benefits to a community. We then need to communicate that we can STILL do this today.