Nitpick: there are third party lenses for the RF mount but they are all manual focus. As you stated Canon has not opened up the spec and so third parties have been unable or unwilling to violate the patents that would allow them to make use of the RF electronics required for auto-focus.
I real shame as I would love to use some of Sigma glass on there without use of the EF adapter.
In fact, Canon is going after third party lens manufacturers that are blatantly violating its patent [0].
One of the problems Canon has faced recently is a flooding of the market with super cheap lenses (we're talking 50-200 dollars for total junk). The people that are buying them are justifiably upset when the photos are crap because they incorrectly think its a camera problem. Hey, a lens is a lens, right?
Anyhow, there's wide speculation that Canon will license to the quality quality third-party makers at some point [1][2].
Bad products is not a reason close specs. Unless you are heavily vested into Canon’s lense ecosystem, or have no issues with money, it makes no sense to go with them; if we’re considering full frames. Glass prices are overly marked up by the body creators and quality is subjective when there’s Sigma.
Do you have a link to the patents in question? Articles I've seen about this are not clear about what is patented and I'm suspicious about whether it would pass a novelty/obviousness test.
A third-party, Viltrox did release autofocus lenses for RF mount. Canon threatened legal action. A quick web search did not find exactly what is patented.
As a result, there is a wide range of third party lenses evailable for Sony FE, none for Canon RF.