What web have you been surfing for the past 15 years? Even in what I call Web 1.0 and you must call Web 0.0 (the static web with Lynx, Mosaic, and little to no user interaction), the web changed as it needed to change, never in versions.
The fact that flickr deploys changes every half hour is unsurprising. If I worked on only one site all day long every day, I would do the same, whether it was me in 1997 or 2007.
If anything, the Software Release Cycle is more prevalent now than it's ever been. ASP.NET brings hardcore C++ developers into the world of the web, and some of them are so unfamiliar with the web that they build installers to deploy websites. Funny, yet sad.
The word "beta" has caught on because it bears the connotation that if the site breaks, it's not the developers' fault for not testing properly, it's the users' fault for not exposing the bug earlier. Brilliant.