It could be quite useful/profitable for a Hollywood studio to acquire the rights-in-perpetuity to a young actor's image in 2023 for $200, if that same actor then goes on to become a superstar.

Well, they're not buying the 'likeness' in most cases as much as they're buying the actor's 'star power' - i.e. their ability to trade on their own name and performance independently of any one media product. That is, simply having their name attached to something makes that thing more likely to do well financially. This is what they're buying - and why casting "unknowns" in a "big budget" production is rather unusual. It's more risky than simply paying, say, Chris Pratt or Scarlett Johansson to perform. As you might imagine, investors don't like risk except the kind that guarantees them returns.