Hmm... I've seen a few high-speed accidents less than 15 minutes after it happened. People were mostly standing on their own legs, except for that one car that hit a tree at high speed even though it was pretty far from the highway (that was ugly). High speed accidents can be and very often are fatal, but it's not as absolute as you're saying.

It's all about the car - don't drive 260 in an Octavia, not even a Passat, much less a second-hand one. Recent Mercedes E-class with all the additional safety equipment can handle high speed crashes well, and the automated systems can do a lot for prevention as well as saving the situation (but there aren't many situations that need saving with the prevention systems).

BTW going 260 in a Mercedes feels about as controlled and smooth as going 70 with less expensive cars. It really is something totally different, and you have to feel it to truly understand it.