Minneapolis Bridge Collapse: Why?

If there's any one event that tells a country that's its infrastructure is shoddy and in major need of repair, surely it is a bridge collapse in a city of three million people. Yet why wasn't the American Government prepared for this collapse, and why wasn't action taken beforehand to prevent this tragedy?

To be frank, I'm not exactly learned about Minneapolis bridge construction, so I can't really point to environmentalists and the like for not building new bridges to accommodate new traffic (although there are quite a lot of bridges in the city). However, it should be noted that the bridge, according to a federal report, was and has been in a poor condition for quite a time. So, once again, why wasn't action taken to repair the bridge?

Like many governments, the American Government is always somehow strapped for cash (except for when giving pay rises ad funding wars). This was a small bridge surrounded by several others, which would only need a relatively small increase in the amount of traffic to accommodate what would normally go over the collapsed bridge. Not a great deal of money would've been needed to properly repair the bridge. In short, it was a failure of the American Government to repair the bridge-not a hard task.

A better, free market alternative would be to toll bridges in the city that can be used for upgrading already existing structures and building new ones when needed. Because no one likes paying tolls, people would be more willing closer to work in the inner city instead of the sprawling suburbs forever in the distance. Only a minimal amount of taxpayers' money would be needed to keep bridges in good condition.

So why let bridges collapse when a market-based solution would be so much more effective?