It seems a little misplaced to rail against Apple as if this is a design flaw. That's how this CPU will perform even in a completely different form factor without sufficient cooling. Want to prevent throttling? Here's a big heatsink with a couple fans attached to it. Want even more cooling? Here's a tank of water and a giant radiator.
Want a slim form factor and an i9? It's going to throttle because it will get hot when you actually use it for something that makes use of that processor. Unless you live where I live and want to use the computer outside in the winter when it's -20F.