I'm sure a big part of it is to avoid stolen tech, but as well, not every decision is made yet, and people don't like to get their hopes up only to be disappointed. Ford probably has not completed decided they are going to do a V8 SC in the Raptor yet, how limited of a release it will be if so, and when it will be available to the public. Better to hold everything till you can answer every question, or give out information that turns out to not be true.
There's also the idea that 'hype' only lasts so long. I've seen commentary that Ford made a mistake by announcing the Bronco almost a year in advance and taking preorders. When we do actually see Broncos on the road, it won't be that big of a deal anymore. Some may get tired of waiting and go get a jeep instead. In the case of something like the cybertruck and Rivian, how many of those preorders won't happen because the customer is no longer excited about it?
Most of those Cybertruck were pre pandemic orders to. Some things have changed. What people want changes after doing pre orders years out. First year models too. Not always the best idea unless you have to have it and want to be that kid on the block. Vehicles do get more refined years after there release.