There are legal limitations on how much a non-owner, even if the future buyer, can do while the current licensee still owns a station.
This is why, often, owners of stations that are contracted for a sale, enter into an LMA which is essentially a type of lease of the station to a third party so they can operate it while the FCC review of the sale is being done. However, an LMA with a licensed station requires that the licensee continue to be "in control" of its license.
In general, a seller has to be very sure of the buyer's ability to close before handing over the station, particularly if a change in format or staff is involved.
In other types of business where the operation is not mostly valued based on a government license, the buyer might be allowed to integrate itself into the operation of the seller's enterprise, maybe even totally. You mention Skydance and Paramount, which are not predominantly FCC regulated so they can "do whatever they want" within the scope of their agreements.
In radio and TV, each transaction is different, but highly regulated as to who has control over the content and compliance issues. It's not like what might happen if you and I make a deal to buy the coffee shop down at the shopping center when we want to start hanging out there every day to get a feel for the staff and customers and, maybe, start ordering supplies or new stools or the like.