Most of the time script comes with 1-2 standard templates and every serious webmaster would want to make his site look unique. More available scripts give more business to designers and actually make their live a little bit easier.

Who actually would suffer from broad variety of available scripts - core programmers/developers.

I think in a way scripts actually help create job for web designer as the need to customise, enhance and do other stuff to the templates that comes with a script or even code a new one for the script.

From my point of view both designers and programmers will always be very searched if we are talking about web. Even though scripts are really complex today, you always find other characteristics you would like to add and since you cannot find always what you are looking for, you hire a programmer. If we talk about design, its the same thing, a designer, if he really is talented, gets a lot of projects.