Does anyone here use Hotmail? Have you ever noticed that with each major Firefox release, Microsoft has to go back and make changes to their Hotmail website so that they won't be left behind in the latest Firefox release?
Would they have needed to do that if the developers respected standards? How much time/money would they save? How much of that time/money would they then be able to invest in newer technologies or new features?
You say that most of the major websites fail W3C's markup and CSS validation tests. Look at most of the websites. Do they look modern? Do they look like the ones that do validate? Are they the first to implement the latest and greatest features or are they stuck maintaining old and outdated technologies, feverishly and tirelessly trying to maintain a house of cards and hoping the winds of change won't knock it down?
There is an opportunity cost for every decision we make. Sometimes the opportunity cost of skipping a standard can forge a profitable business partnership. Other times, especially when standards aren't followed because of ignorance, the cost is being left behind because of bugs, random behavior, and guessing games. Sometimes, following standards can create a platform of extensibility where new features can be added for years to come.
