I began getting a sense of this some time ago.
...Blog platforms can be customized beautifully these days with a fraction of the development time and cost because the entire backend of the site is already done. That’s a huge shift for the web design business because traditional shops (and I’ve worked for and with some) would have their own code set for building sites or they would start from scratch. Customers got charged like crazy for sites that would really be no big deal in this day and age. The worst part is not everyone knows this and some web shops are still selling their services like always.
This blog, though I could, isn't even customized directly in the CSS (cascading style sheet) but is rather just a stock template that I've customized within a limited range of parameters TypePad provides, such as colors, fonts, link styles, title styles, and so on. Basically, just like creating a fancy Word template that you then use over and over. So I have several different page designs which are saved as templates. The front page is one, the about page another, and then there's a generic page style for displaying posts past the first 10 or so here on the front page, and also categories and archives.
All the content, i.e., the posts, images, comments, etc., are all stored in a sort of a database and then that content is transfered into one of the templates in response to the link a person clicks on, and also links within the content itself to display things like images and whatnot.
My first company websites I built myself, the first in 1994, I believe. Hundreds of hours. Then, later, I hired professionals and all told, we've probably spent near a quarter million in the last 10 years through about four designs and re-designs total.
We still are sitting on a hand coded site. Here's another of ours. Any time we need to change anything is a major hassle, and expensive. So we do what lots of small businesses do. We let our websites kinda collect dust. Now, here's what's been in development for only a few days and will soon move to the root directory and be our new presence (it's being worked on now, so no telling what you'll see at any given moment). WordPress. At any rate, the company we hired to do this gave an initial budget of...drum roll...$1,000 (not a typo). Then they took our contact form that integrates with salesforce.com, made it into a widget we can drop anywhere, and are currently taking our debt calculator and making a widget of that too, all for another $1,000.
Of course, there will always be a demand for the complex websites that actually perform some service via the interface, but if the company website is principally to convey information with very little in the way of bells & whistles, then a blog-based site is ideal. Not only is it quick and inexpensive to put together, it's whole raison d'être is to provide a means for constantly changing and adding information, content, which also serves the purpose of keeping the company website fresh, relevant, and (hopefully) linked to.