I am sorry but this argument is not gonna fly. Saying that governments are infallible and make perfect decisions or trend toward perfect decisions is simply not correct.
And assuming you mean democratic governments this makes even less sense.
In that case, I'm glad only you said it -- I never did. Government is the art of the possible, and politicians generally know how to avoid being thrown out of office. Avoiding decisions that have no public support, choosing only those that have some public support, that's something politicians are good at. It's the political version of crowdsourcing.
> And assuming you mean democratic governments this makes even less sense.
You serious? Finding out what the voters want is even more important in a democracy than it would be in a totalitarian state. Political opinion sampling is why France and Japan have high-speed rail, and it's why the U.S. doesn't.
Politicians in a modern democracy do indeed need to stay elected but that is typically independent of what a true, unfettered democracy would produce. Some of this is by design -- a pure democracy would be largely unworkable. At best too fractured and at worst everyone would vote for more benefits and less (no) taxes at the expense of national debt for a future generation.
Mostly politicians vote for what keeps them in office. Which as we see in the US is typically special interest groups and powerful lobbists.
True crowdsourcing occurs in free market economies. We could go there :) The libertarian would say if high speed rail was so in demand and made such economic sense then why arent companies scrambling to take advantage of a market inefficiency to make gobs of money?