It's like using cheap stock photography - it's ok, to a certain level, but everyone will know you've used stock photography and that's probably not the image you want to project.
Lol guess so. I'm not sure the difference is so obvious at the client end though. With the visual side, it's obvious there's a difference.
When the difference is all under the hood, I think it's probably more difficult for the client to tell. That's not to say that the under the hood stuff isn't important.
They're the only ones who really fuss about it.
Still, who knows, by the time my build skills have improved, I might be saying the same as you.
Since graphic design/web is so subjective, despite all the fuss designers of each discipline make, levels of professionalism is a bit hard to measure I think. If people are willing to try and build themselves an extremely ugly template website in Wix and Co then there is clearly a market for those at the 'lower end' of the web spectrum.
Text in images, inline styles, no external (and so cached) stylesheet, tables, image maps for links. Whoever the 'people who know about these things' are you've spoken to don't know squat about coding a good layout. It just flies in the face of everything you need to be competitive online nowadays. It is the usual story with WYSIWYG, on the face of it, it looks great but there is some seriously nasty stuff lurking just below the surface...