I agree with everything you've said here, but I think we should understand why it happens and build a better solution to it rather than lamenting the fact that

I agree with everything you've said here, but I think we should understand why it happens and build a better solution to it rather than lamenting the fact that people will always try and avoid doing difficult things when those things should be easy. We have a situation where these "correct" elements have different sets of default styles in different browsers and require different sets of styling rules to make them look how the designer wishes in each. If your starting point is that is it any wonder that sites are generally so shitty? A good starting point would be true separation between the semantic and the visual.