I see comments to this effect every now and then on HN (ie. any skilled team could build out Facebook in 30 days)
It's great to shoot for the stars and have faith in yourself, folks, but shockingly lots of people who get paid to program also happen to be REALLY GOOD at what they do.
While I could focus on the benefits of a little bit of humility (and they are many) instead I'll say that there are people who come on to these sites and see ridiculous statements like this and will suddenly start to wonder what's the point of learning to code if they'll only be good once they can build any app in a weekend.
So no, there aren't people who can build any app on the market in a weekend. And that doesn't mean that any of those people are bad at what they do.