You've got quite a few facts wrong in this short rant.
Nokia isn't working on a Theora DSP decoder. In fact Nokia along with Apple were among the strongest voices against including Theora as an interoperable baseline codec in HTML5. (It was revealed, but only later, that Nokia are, like Apple, in the MPEG patent pool). Mozilla are writing the software needed for "hardware" decode on the n900 and similar platforms.
If a DSP decoder counts as an independent Theora decoder then there's several other things that would count too. I would have thought the ffmpeg Theora/VP3 decoder would have counted by any measure.
The On2 code was rewritten, even for Theora 1.0. Theora 1.1 was another major rewrite but mostly of the encoder (though that work also made the decoder faster).
While more an omission or curious framing than an incorrect fact it could be suggested that since Theora is BSD licenced then there is little need for anyone to rewrite it. This is unlike, for example, H.264 where there is no liberally licensed reference implementation (and some experts from x264 think that most independent implementations are atrocious since the spec is easy to mess up). So you seem to have portrayed a strength as a weakness here.
You (or someone else round here) have claimed before that VP3 was never licensed to a paying customer and this is why it was released as open source. I don't think this even makes logical sense, but moreover I believe it to be entirely untrue. Do you have a source for this surprising claim? (The official On2 line from the guy who suggested it is that they open sourced VP3 to "scorch the earth" for competitors as they moved onto the next generation codec)
On2 backported changes introduced in VP6-8 and VP6 improved measurably as a result.
Microsoft only introduced H.264 decoders in Windows 7.
Microsoft are also MPEG patent pool members.