In pure business terms, there are a couple of considerations that may have come into play here that I think people discount because they think "a game is art" rather than that developers are businesses with employees to pay and shareholders to consider.
Firstly, the Witcher world games outside the main titles (so I'd guess Gwent and the other one) badly underperformed, depriving CDP of an income stream they had planned for (I doubt the resurgence in W3 sales on the back of the Netflix series had any impact on financial planning because it came very late in CP development and, in any event, may or may not have been a flash in the pan).
Secondly, if you have already booked a global marketing campaign and spent the money on it, shifting a release date can become very problematic. In the worst case, you may have to run the whole campaign again, essentially flushing 100 million dollars or so down the toilet. Not every company is big enough to absorb that. (Compare No Time To Die, for which Universal had already launched worldwide billboard and other advertising and started the press tour before the film was pulled; if it gets a theatrical release Universal may have to run that whole exercise again and it will cost a fortune). Missing Christmas is also seriously bad news for sales.
Third, contrary to popular belief, GOG is not Steam and makes laughably small amounts of money for CDP. They're not in the same position to do whatever they feel like with cash rolling in as Valve.
Developers are projects-based businesses. They have to bank a certain amount of income from the good years to tide them over the lower income years. Otherwise, they can't pay for future development. At a certain point, the financial hit of delaying a release may be too much of a risk to take.
Which is not to say that the launch went smoothly, that the game was released in an acceptable state, that management was unimpeachable, or anything else.
But game developers do not live on air. There may well be sensible business reasons why things can't always go to plan.