instead of 'actual doers' I'd start to blame idea-mongers: Dave Winer for his "Easy easy easy" motto which drove us in the 'Edit This Page' paradigm, Tim O'Reily who has succeeded in bringing in a fashion Web 2.0 Design Patterns and Business Models and idea of Monetizing a User-generated Content, and, finally, if all fails, William H. Gates III and IE team who introduced a MS DHTML Editing Platform in their browser, making possible in-browser web content editing. *smile*
"It's not Safari's fault because they use Open Source code."
yes, but rather because implementing features compliant to existing standards have a higher priority in their dev. schedule cycle than support of may be useful but not yet commonly standardized features already implemented in browsers of other vendors.
"It's is TinyMCE's fault for not coding it in."
no, but rather because they have a priorities of their own, based on their evaluation of each browser's market share.
"It's the fault of WordPress because they use Open Source code and should have chosen better."
I don't think so: at the time when Matt was looking for a RTE, TMCE was (and still probably is) most closely corresponding to the model and goals of WP.
"I don't see them if I use Lynx"
nither do I, also when using handheld device browsers. that's why I believe it'd be a 'Right Thing' if .com had installed a plugin which allows to input a simplified markup like 'MarkDown' instead of having users to muck on with raw HTML. it is also particularly actual in view absence of the 'post-by-email' mean.
added in closing:
the funniest thing in this story is that Safari's official blog is powered by... yes, WordPress! ;-)
one from an excellent theses list by John (GD):
"Web apps aren’t really cross platform. Different JS implementations mean that they only really work in one or two browsers, and there’s almost no standard to follow."