Dude is essentially a rookie. What did people expect?
I remember a few years back when Jennings went off on a hot streak for "X" number of games and people got all excited about that too. Heck, I think Jennings actually scored 50 pts in one of those games. Yet, once teams started to figure him out a little, he came back down to earth.
That is exactly what is happening here. And just like Jennings, Lin stands a decent chance at recovering, improving his game, and becoming a good player in this league. All-star level, probably not.
The hype he was receiving is just a product of the way the media works today. Always looking for the "next big thing".