Just read (Nasty Bits) the essay on famous chefs and whether we should have an expectation of them being at their restaurant.

First of all, you write with a point of view that is somewhat biased by your own status as absentee chef..

However, to pull into this discussion forum, I've been to several European restaurants featuring 'famous chef's and almost without exception, the famous chefs are there cooking, and chatting up the crowd after service.
In Spain..
Arzak - lunch service, and Juan Marie and Elena are out in the restaurant.
Can Fabes - Santi Santimaria is seen prepping and preparing during service
In London..
Le Gavroche - Michel Roux makes the rounds after service
Germany,
Dieter Muller - Makes the rounds as well..

Seems to me that only since America has created this new 'celebrity chef' status, we've now seen our best chef's leave the kitchen.

Ferran Adria - still pretty involved, right?

It can't be a good thing for customers to have Thomas Keller less involved in the kitchen?

You are right that most celebrity chef's are not in their kitchens. It's perhaps the naivete of customers who still ask to see them, that you are most put off by.

But it is most certainly not a good thing for the customer, that the top chefs are not overseeing the day to day of their kitchens. It's just the new unfortunate reality of food tv and commercialism..