I think Linus is dedicated to his craft, but in the last two decades, the complexity of the kernel has gone up exponentially, due to adding capabilities, supporting more advanced processors, and increasing speed/efficiency.
He began by writing a kernel single-handed, for fun. And now his creation is simply beyond his, or any single person's ability to comprehend in its entirety. But now here is a technique that can be queried about any component or concept, and provide a generally reliable explanation or correction, or addition, or expansion, and he believes (and for the most part I would agree) that he is knowledgeable and skilled enough to evaluate the quality of the code produced, a genuine centaur as defined by @pluralistic .
The risk, of course, is that this will greatly expand what Linus believes is under his control to maintain, modify, and improve, with greater and greater reliance on the tools over time.
In finance, the caution has always been "past performance is not indicative of future results", but humans, by their nature, have gone broke for centuries by ignoring that adage.
The result will be elements of the kernel that have not been as carefully scrutinized, or written as comprehendibly (and let's face it, without years of experience, a significant part of Linux isn't comprehendible *now*), or clearly documented (ibid.).
Others will try to emulate Linus' workflow, with varying degrees of success, and the result will be bodies of code that can only be maintained or repaired by using the tools that generated them in the first place, and the level of abstraction will increase beyond that developer's ability to comprehend, ad infinitum.
Right now, I've stopped updating my various machines running Debian, because I have no idea what's going to be introduced, and I'm nervous about moving to NetBSD because of (a) the learning curve, and (b) what functionality I'm going to lose because one or more of the tools I'm using now won't be available…
It's like those factories where there's one dusty old PC running Windows 95 that can't be replaced (or even touched) because it's critical to the operation of a particular machine, and there's no viable alternative.