I don't really get why people get wound up by it to be honest. If you don't like a certain book or price of a certain book you simply don't buy it. There are certain King books I know I will never own. I'd like to own them but barring a lottery win I never will. I already own expensive (for me) books that non collectors would shake their heads in disbelief at the price paid for them. I would buy a lettered Carrie tomorrow if I could afford one but I can't - and to those that can and are willing to pay the price asked for one I say good luck to them!
I don't NEED another version of 'Salem's Lot for example. I have the Centipede Press S/L and Gift editions as it is, but I've ordered both the PS and Cemetery Dance anniversary editions because I can afford them and I want them. I'll probably never own a Centipede Press lettered (or equivalent of) 'Salem's due to price, but I can live with that.
If lettered books get to a price where even people who can afford them won't pay the price asked, then that's when they are overpriced in my opinion. I'd love nothing more than to be able to be a Stephen King completist but I never will be able to be one. I already have a collecting illness as it is without being a completist!