I agree with most of what Patrick says above. I'll just toss out there that I think the margins are narrowing. EPS, the sharing of knowledge etc. have made things closer. The VAM clones by all reports are pretty much indistinguishable from the real thing. I suspect the X68 is closer to an SL bike than the x38 is to a Foil. Time will tell.
Its not impossible, even with the price difference. Again, look at the US tariffs going back to Trump 1. There's a good reason that carbon frames at $600 were exempt at the urging of Parlee and others. There have been plenty of reports to sort of place the actual cost of most outsourced framesets in that ballpark. Now, aside from marketing, sponsorship, cache, and multi level distribution, what accounts for the retail price of a real SL8? I don't doubt there are some corners cut, but several thousand dollars in corners? An SL8 frameset is over 3k. Without a handlebar/stem. So yeah, for some of us cost is a consideration.
In my case the algebra was simple. I'm 65. Its questionable whether I'll be comfortable on an aggro geometry bike (and for how much longer, lol), and rather than risk 2500 or so on a used sl8 to find out, here I'm risking 700 bucks. If the geo works and the bike is nice enough, I'll hang on to it, if it sucks in either ride or fit, its not an economic disaster. I've had non clone bikes from Hong Fu etc that were fine, and while this is a more sophisticated thing, I'm not worried.
Still, I'd be willing to pitch a hundred bucks Patrick's way to help fund an x68 back to back, out of genuine curiosity as to how close or far from an acknowledge halo bike it is.
PS-I hear you, Patrick about the "softness" of the sl8 relatively. Its why I sort of chuckle at reviews of the x68 that say its "slightly soft". Hell, the real thing is.