Ironically, as I've said before, it's also pretty much what mainstream bible scholarship says, but for some reason they basically still call one of the guys in the mix (which may be real or not) the Historical Jesus. It's a really bizarro world, where at least parts of the opposing teams are more or less making the same claim, but they still call each other wrong
As I was saying before, even Ehrman will cheerfully tell you, and for that matter say it in lectures all over the place, that mainstream scholarship for more than a century at this point is that:
A) no more than 30% of the sayings and ideas attributed to Jesus could have reasonably been said by the same person, and
B) there is more than one set of those 30% -- i.e., more than one person -- that can be reconstructed, and scholars disagree as to which is the real Slim Shady
That's not fringe and not even new. It's bog standard bible scholarship at this point.
So basically at this point the only difference between mainstream scholarship and your Christ Myth version is basically just this:
MJ: well, then it's a composite that never existed in that form
HJ: yeah, but one of those parts of the composite -- more specifically the one _I_ cherrypicked -- is the Historical Jesus
Derp