Unfortunately the flexible implementation has a better chance at becoming dominant as it will work in more cases hence user are more likely to adopt it­. Users

Unfortunately the flexible implementation has a better chance at becoming dominant as it will work in more cases hence user are more likely to adopt it­. Users don't care about standards compliance in the short term (if ever), they just want a solution to their use case, which is understandable. Same reason Microsoft worked so hard to keep deviant apps running on newer versions of Windows, there's a quality to "it just keeps working no matter what I do".