I understand.
"aliveness" in the martial arts sense has a very specific meaning, according to certain "modern" schools, and it's not a new concept, obviously sparring has been around for thousands and thousands of years. Roman gladiators sparred, Chinese soldiers sparred, Indian warriors sparred. Whether or not its practiced in a particular school today depends on specifics.
But I think the answer to your question is simple, if you want to keep it specific to Japanese kata. Kata is not for leaning to fight. Never was. It's for learning movements that were developed from older movement sets, a long time ago. Any one of us here who knows a little boxing and a little kata could probably created a 100 move Boxing Kata form containing nothing but functional movements. Without sparring with them, they'd be nothing more than practice, though.
When boxers learn their first movements, they learn dead forms and patterns (kata, in the literal sense), before they ever hit anyone for real. They learn form/pattern and the functional use/skill comes later on. Nobody goes into a boxing gym, gets thrown into the ring, and is told "just go". It just so happens you'll probably be able to do that in a short time, because boxing forms are pretty simple and limited to a small range of attacks and defenses.
As long as something in karate, kung fu, or boxing instills some sort of benefit, it's not "useless". The Shaolin fom you posted teaches balance, grace, and flexibility, and contains specific techniques that can be drilled or sparred with alive. So that video is not representative. The karate kata teaches energetic movement, intention, focus. Also not representative of how kata movements are utilized in full contact competition.
If kata were truly useless, they'd have died out a long time ago. They'd have been left behind for impracticality. Yet millions of people find them helpful, compared to the few critics, and quite a few of their proponents are, and always have been, successful, full contact fighters who train "alive".
