Flash-in-the-pan refers to the fact that he's only produced at this high level for 25 games. That's not enough time for teams to design defenses specifically geared toward him. It should also be noted that he did that under D'Antoni's offense which is very different from whatever McHale is running. Now, all of the signs point to Lin being the real deal but I want to be cautious until I see him going up against the likes of Nash, Westwood, Parker. The great thing about Lin is that he knows he has weaknesses that must be addressed and is willing to put in the work to get better.
You realize that the Knicks were not really running Dantoni's offense when he quit right? He played 7 games not under Dantoni's offense and arguably he played his best basketball under those 7 games with Woodson. And trust me teams scouted him. Rose forced him left all game, Rondo was prepared for him, the Spurs knew that Amare is a terrible pnr defender and Lin can stay in front of his man so they took advantage of that. The raptors double teamed him and when that didn't work ran the zone defense (which did work) I can't remember the rest. With all the hype surrounding him teams definitely scouted him and created defences targeted towards stopping him. Nobody wanted to be a victim of "Linsanity". Deron Williams was so focused on outscoring and keeping him from going off that it bordered on the obsessive to be honest. For a guy who took the season off in NJ he was really motivated then because people were saying that he got lit up by a rookie. Now what I will say is that with the Knicks he was surrounded by a lot of talent so it either you let Amare beat you or Melo beat you or Lin beat you.A few teams dared Lin to beat them (Sixers game and pacers back to back etc). Now that he doesn't have Melo and Amare around him it will be interesting to see how he handles that.
Morey is not trying to build a winning team by acquiring Lin and Asik. He is rebuilding this team because the recent team didn't work. So with Lin, he will make Houston money but he is also young and can grow with the team. This is rebuilding, not trying to contend.
not to mention, I think he gets those 5-10 minutes from McHale for toughness/attitude/effort alone. McHale will love him, and he'll be given a chance. On the other hand, what's the point in keeping him on the floor for Adelman? Be the main high post facilitator? i very much doubt it, too rookie.