Will expensive shampoo solve your hair's woes?

As I contemplate buying an insanely priced bottle of Kerastase shampoo, I can't help but wonder whether $$$ shampoo is really the answer to healthy hair.

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In an informal survey I've conducted of those sporting beautiful, long healthy manes; it seems like the answer is no.
These chickies usually buy d/s shampoo and spend their cash in conditioning treatments, great heat protectants and top of the line styling tools.

I was thinking that shampoo doesn't really stay on your hair long enough to really do anything, does it?
I mean, the primary purpose of shampoo is to cleanse, and if you use silicone base products, to gently remove this ingredient so the hair doesn't get coated.
In that case, buying a gentle yet effective silicone removing formula should be enough, right?

I am one those that believes that facial cleanser should only do what the name implies: cleanse.
I have found that if I intend for my cleanser to: clean pores, refine texture, treat acne, act as anti-aging treatment etc... I am usually disappointed (and my skin inevitably gets irritated)
Then why should I expect something different from shampoo?
After all, facial cleanser is to face what shampoo is to hair, right?
Maybe if expect a $40 shampoo to be worth $40, I will just be setting my self for disappointment.

Now, I am not talking to abandon my beloved L'Oreal Professional Intense Repair shampoo for Pantene or Dawn dish washing liquid. I'm just thinking that maybe my money would be better spent on other things....

What do you think?