I saw that video you're talking about I think. I might be getting some prices mixed up but I'm thinking I'd seen a PTR listed for ~$1700 or so. At $2100, that's still $400 difference. It does close the gap significantly but that's still $400. Of course, this is assuming the prices for the other clone-likes are fixed. It could help drive the prices of them even lower...competition is a great thing.
If HK makes these in any quantity, the prices on several things could come down. I doubt you'll see any huge drops, but they will will probably step back a little.
A $5K HK 94 might be a little harder to sell. The bottom won't fall out of the 94 though, because it is a German made rifle that that is pre-922R. Doesn't need any US made parts to turn it into a SBR. The new SP5 will need US made parts to legally convert to a SBR.