Even when the need for accessible design is understood, many web page authors regard it as a constraint on their ability to design attractive sites for their clients. It's easy to be proud of your Web site. It's another thing to have people say it was visually appealing and easy to find everything. HTML isn't PostScript. Until good tools exist, web designers will continue to be used as human shields in the browser wars, with our customers being the big losers as they pay us to make two separate versions of everything and serve HTML out of custom databases.
Web pages are about communication, design is about communication.
Over many years, the publishing world has developed a visual language which encapsulates sets of unspoken rules, e.g., serif fonts for blocks of text, sans-serif for headlines, short line length, the importance of white space, different styles for different functions, techniques for drawing the reader's eye into a story. Web pages are, after all, still about communication. As a result, many of today's sites are starting to have elements common to the look of their printed brothers and sisters. This can all be done with a bit of HTML trickery. And that's all to the good.