I started off in the "enjoying collecting gear" quadrant of photography, then I heard an insightful comment by a pro: "If you have $5K, you can either buy one good lens and use it to take photos of the pigeons outside your apartment, or spend that money on a destination holiday and take pictures of amazingly beautiful places with your old lens which still works perfectly fine." I stopped buying new kit and started go…
That Z9 will be yesterdays tech in a year or two, and you'll be able to pick it up for a fraction of its current price. It'll still perform exactly as well as it does today, but the gear heads will be onto the next new thing.
It probably won't see significant price drops for 5+ years, because the pace of development in the DSLR market is slowing down. There are longer and longer gaps between new significant features, which means the price of used cameras isn't going down as fast as they used to.