The title question does not imply designing without thought or skill. What I'm referring to, is who designs websites purely for content or eye appeal? One example would be using Flash, even though many critics warn against Flash sites. But I have discovered that companies serving local areas like a single large city, may do well with a catchy looking website, for traffic from ads and business cards: not from search engines. I've got a notebook with 200 or so business cards, and it's amazing that although most have a website address, only about 1 percent put their URL prominently. Those are the smart ones. Because anyone will look high and low for a phone number if they want one. So the website address is what should be in larger letters, with the phone number in tiny letters at the bottom instead. Likewise with many brochures and yellow page ads. Anyhow, I finally came to the conclusion that websites can be done well in two different ways. One for the search engines, and two for printed brochures, cards and other ads. Often, websites can accomplish both. But I find jazzy flash sites to be poor for SEO goals in many cases. And personally, I like some of the creatively done flash sites, even if it isn't my own cup of tea.
From my experiences with web designers, a lot of them just design for the beauty of it, with zero, absolute zero considerations for SEO, even if you feedback to them, they will think it is an infringement on their creativity. It isn't easy to find a designer who can design quality and with SEO in mind.
I'm a huge fan of flash, when I made my jazzy flash site I also made an html version for seo purposes and for people who may have a slow internet connection. It's great because some people prefer the flash version while other people prefer the html version.
I would say in a lot of these cases the problem is not so much coding for SEO, as just plain piss poor coding in the first place. To me, SEO should be a natural occurance of just writing the code properly - all the 'black hat' chicanery of trying to game the various engines that fills entire forums tends to boild down marketing scam bullshit or the tools of marketing scam artists and the nubes who fall for the get rich quick nonsense. Too many 'designers' start out in a goof assed paint program first, shoehorning their final content into their pages. In general, I'd say MOST of your people that start out with a PSD are going to have CRAP in terms of minimalist semantic markup, and as such are starting out with their hands tied behind their back so far as SEO and accessability goes. The net result is usually a miserable /FAIL/ - the content shoe-horned into a graphical layout that is almost guaranteed to not only prevent people from finding the site in the first place, but the bloated garbage will make repeat visits even rarer. (Seriously, what the devil is up with these 1meg websites made up of 200+ files?) A lot of it is indeed goofy eye-candy bullshit, like the crap your various flashtards churn out, or the use of DHTML/AJAX for stuff that can be done WITHOUT javascript in the first place or that causes major accessability headaches because of it. Flash is for games and videos, NOT presentational elements on a website - using them for such is a miserable /FAIL/ that hinders every site that does it - hell, I browse with plugins disabled for the very reason I got sick of 1 megabyte flashtard headers on pages that don't even have a quarter K of actual CONTENT. All you have to do is look at 90% of the rubbish people link to in their sigs around here for examples of piss poor coding and design.
Personally, I like very simplistic designs (no millions of colors, retarded buttons everywhere, 100 images on the homepage and other BS). But sometimes it's just plain impossible to explain to a client that the design he wants is totally horrible (especially businessmen still living in 1996 who want to have background sounds on their websites, millions of useless anti-user-friendly features etc...). Moreover, explaining SEO, web standards and such to clients is a tough job.
From what I've seen very few websites are SEO based. It's amazing the amount of big companies that don't use it. Take for example Microsoft.com The title is hardly optimised, Javascript is rampant, the alt tags make no sense. And this is a company who OWNS a search Engine (And most of the world ). The only reason it does well is the PR 8 Homepage. What is the chance a average HTML user will know about SEO?
I'd go with the method of designing the site in pure HTML/CSS then adding JS/Flash where appropriate, my main features or SEO goodies will never be in JS or Flash unless they are definatly readable. Depends on your site objectives of course.
Lots of designers have no clue. They started off in printed media, and offer websites purely because clients asked for them. Their designs are overloaded with images and have poor accessibility (and thats just assuming that anyone will sit around for 5 minutes waiting your site to load - and I shit you not, I have literally seen pages that take 5 minutes to load on 256kbs broadband, let alone dialup) Those websites result in high bounce rates, bad search engine rankings, sales that wouldn't even buy a packet of gummy bears, and ultimately they hurt the businesses reputation instead of building it. I disagree. There is only 1 good website, and that's one that looks good, and is accessible to both all visitors and search engines. Just SEO = Fast, bad for visitors, makes your business look tightass because the design (or lack thereof) sucks, low sales Just Looks = Slow, bad for visitors, bad search engine rankings, low sales