Oh, and in the case of Google. Anyone could build what they did with 411 in a week these days. You take the Foursquare / Yelp API's + Wit.ai + Twilio and your'e good to go.

In order for them to do what they did they first had to:

1. See into the future.
2. Understand folks would walk around with computers in their pockets (smartphones) and having humans command them by voice where applicable would be perfunctory.
3. Aggregate business listings data. There were no listings API's back then. They had to do it the hard way.
4. Design the first voice recognition interface and have it "barely functional." If you recall Google 411 was super buggy at first - that was the point. Collect your queries and make it better.
5. A lot of other stuff.

There's probably a million and one other things I didn't list. Pay particular attention to item #1.

They first had to see into the future.

It wasn't easy. But they got there and they're still pushing (Google Glass for example). When they saw into the future - they didn't look down the road and see $$$ signs. They saw one word; "awesome."

We get to glimpse into the future everyday. Each day we get more excited about it.