It seems to get worse and worse every year in that regard...
I'd like to blame it on the photoshop jockeys as typically that's all they know how to do -- but many of the sites I doubt anyone with any artistic sense was even involved with. (Yahoo and CNN are great examples of this)... I very much doubt a 'designer' was involved.
I'd like to blame it on laziness -- But I've always found fluid sites and dynamic fonts with dynamic containers EASIER to create since you don't have to sit there screwing around with the math as much as everything adjusts to the content -- and such layouts are usually LESS prone to breakage cross browser...
So that just leaves ignorance -- which is evident in such sites crapping out pages filled with fonts declared in px, the crappy fixed widths you mentioned that are too small for my desktop and too large for my netbook (that get even worse trying to use something like a pad or smartphone)... and to compound it even further we see the typical "color contrasts for legibility, what's that?" attitude on many such pages.
But it comes down to people who never bothered learning to do things properly in the first damned place and are COMPLETELY unqualified for the jobs they are working. Further proof of the outright ineptitude and ignorance of such developers are apparent the moment you look at the code coming from such brick outhouses. One look at the source code of the STOCK turdpress template is sends you into such shock over the FLAT OUT INEPTITUDE of it's coders, it's a miracle anyone is DUMB ENOUGH to try to use it -- and most off the shelf CMS are actually WORSE... much less corporate websites for mega-houses.
Yahoo is similarly afflicted. 4.3k of plaintext, 229 anchors, and 14 "content" images on their home page, so naturally it needs 163k of HTML... NOT. That's THREE TIMES as much HTML as should be there, and of course the megabyte sized page load... for that... RIGHT.
SO many developers, especially at places like Yahoo piss all over accessibility at every opportunity and just sleaze out their work any old way -- not caring that it costs the company they work for money in hosting costs ALONE (kiss off raises this year), makes more work for themselves on maintaining it, and in general makes them look like such idiotic fools that even non-technical people can make fun of them and their idiocy. You want to know why Yahoo has been an "also ran" for about six or seven years? THERE IT IS! Shockingly bad...
Though as Stephen Colbert said "I for one am shocked... Does Yahoo still have customers?" (2 minutes in)
Or as I've been saying for the better part of a decade -- taking web development advice from Yahoo is like taking technical advice from Forbes or financial advice from Popular Mechanics.
Bottom line -- This is EXACTLY why I am disgusted with the entire web development industry as a whole at this point; endless lame excuses being used for developers to not do the jobs they were hired for or to cover up that they aren't qualified to do so.
Though it does come down to Hanlon's razor -- Never attribute to malice that which is adequately explained by stupidity.