> It takes thought and creativity (and research)

And money. Lots and lots of money. Sometimes, especially with single-page sites, it can take more than 100% of the base budget to implement the progressive enhancement necessary for screen readers and the like.

Customers don't want to pay for it, and I'm not going to do it for free.

Your point in 2 needs to be backed up by some numbers. You can't appeal to someone's internal economist without some statistics.