I really dig these!
Why Rackham just doesn't release 'unpainted' versions of the same minis is beyond me....Even if it's only available in 'limited numbers'.
I honestly do not understand your problem with pre-paints.
If you want to paint them, then just re-paint them. The shown example proves how easy and good it works.
The benefit IMO are a good range medium quality painted minis to play with.
In most game shops you have to play the greater sin of wargaming: "UN-painted" minis...
I always prefer a pre-painted army.
And the Cost vs demand arguments holds also some truth to me...