I don't understand what you mean. I'm using the original vccv TeX algorithm in my Sweet Justice library and it works decently. There is also Hyphenator which uses Liang's algo and supports dozens of languages. The web case is very similar to the desktop publishing case.
Web/DTP is not the same thing at all. DTP is static. The web is dynamic.
You can envision some paragraphs of text in a blog post being re-flown but the web is more than that. What about interactive text? Text in SVG? Multi-language text in the same paragraph? Various stacks of text in varying z-indexes, css-3 animated? Text manipulated with Ajax? In a mobile browser AND in the desktop. Not so easy anymore when you have to cover all of those --and possibly in a W3C or HTML5 sanctioned way, compatible with concepts like "overflow" and all.
