Hm... I have to be honest, I don't really understand why that would be the case. What exactly about an "intermediate" ski would promote good technique and prevent me from developing bad habits?
2 Seasons with good progression certainly doesn't make an advanced skier. I am far from it to be honest and realistic. But at the same time, I have enjoyed it, have gone frequently, and tend to take lessons about every 3rd or 4rd trip.
I guess the one thing that I was worried about and thinking about when deciding whether or not to purchase skis was whether I was at a point where I could realistically predict the type of ski I would like to ski when I am quite a bit better than I am now. I really don't think I was or am prepared to do that as of now. But, I haven't talked to many people who have claimed that skiing on an "advanced ski" would hold me back, make me develop bad habits, and hinder my technical advancement.
For me personally, since I started demoing "advanced" skis 5 ski trips ago, I have made bigger gains and felt far more comfortable and confident than when I use to rent the standard fare skis or the "sport/performance" skis.