It's one thing to know html inside and out, but why not take advantage of quickly tacking up a general design and coding around it to save time and effort?
That's why I mentioned I don't code for a living, therefore this is [for me] a non-issue.
I would imagine most web developer / design firms would most likely use one of their own custom built templates as a start to work off of (at least, this makes sense to me). This would be the ultimate time saver (once templates are build, be it via WYSIWYG or otherwise, working off of that would be even faster down the road if a particular template suites a particular project's needs [build enough of them, and there shouldn't be too much of a problem]).
Thus, one could argue (I suppose) that all WYSIWYG is useful for is initial layout setup for the purpose of template constructing... Afterall, why re-invent the wheel when you have a many templates stockpiled around that you can work off of? It's even faster to manipulate a ready built template than even doing things via WYSIWYG all over again from scratch.
In any case, I for one am no fan of those aspects of IDEs and will stick to hand-coding everything (with the use of code suggestions, drag and drop functionality to generate certain tags among other shortcuts).