No, hypersonic missiles have been around for a long time. From 88 to 92 I worked with the National Aerospace Plane X-30. We had materials that would sustain well over Mach 10 that were SUPER lightweight.
Our problem was the scramjet that we couldn’t get above Mach 8 at the time. Since then, they’ve had a lot more success.
(Our goal was Mach 25!!)
The X-30 was still exo-atmospheric. I have read about hypersonic, non-ballistic missiles but they have not hit the 5k mph that the article is talking about. I do believe that the theoretical limit of scramjet was Mach 8 as you stated but once again, these are for the upper reaches of the atmo since the air density is conducive to such speed.