Why is the saddle so far "maxed" rearward?

I always suggest possibly using a longer stem so as to move the handlebars forward in lieu of moving the saddle rearward to accomodate a rider's torso length.

The rearward saddle position stresses components and takes weight off of the front wheel, which invites flighty steering response.

A rearward saddle also requires the rider to bend more sharply at the waist to achieve a given amount of weight ahead of the pedals or to achieve an aero profile, which limits the amount of power that one can comfortably sustain.

And a rearward saddle position requires a much greater energy-wasting "heave" to get out of the saddle (in order to attack hills, cross road defects or effect acceleration).

So there are good reasons why bikes are not sold with their saddles forced to their rearward limits.

I often encounter riders with saddle set rearward because they found they were sliding past the rear edge of the saddle, which is actually the first symptom of too low of a saddle height.