I don't think any of these castles were built directly by kings - although I suspect their construction was either approved by a king or by someone who had delegated authority from a king. NB I can also see a large castle about ~11 km away that was a royal castle (and still has a military garrison).
I suspect that most castles are probably in other people's kingdoms.
1. Has strong norms against castle seizure or abandonment of the king's duties in kingdom upkeep
2. Has a federation of non-king castle owners strong and unified enough to force the former point.
In practice, unhappy nobles would often rather deny their necessary cooperation (at war or administering the land in peace) and thus force the king to make some amends and tradeoffs.
Passive aggressivity isn't a modern concept :)
Example: Valve in the early 2000s before or as they were building Steam to challenge the video game publisher model. 20 years on and Valve is still printing money, while Sierra Online doesn't exist.
Unfortunately Sierra had to accept the offer.
Well, there is the practical purpose of legitimacy. It may seem too soft for modern power theoreticians, but the legitimate king has something that cannot be acquired by raw power, and that puts somewhat of a damper on potential rebels. Not on each and every one of them, of course, but it has a wide effect. Killing or deposing the legitimate monarch was a serious spiritual crime for which one could pay not just by his earthly life, but in the afterlife as well.
Even usurpers like William the Conqueror tried to obtain some legitimacy by concocting stories why they and nobody else should be kings.
We still see some reverbations of that principle today. Many authoritarians love to "roleplay elections", even though they likely could do it like Eritrea and just not hold any. It gives them a veneer of legitimacy.
Castles are thus more like domains where once you take hold of it, even the big powers have a hard time taking it away from you again
> Building a castle is a very good idea if you seek to entrench yourself in the power structure of the kingdom. To do this, you must be able credibly mount a defence of the castle to discourage forcible eviction without major mutual destruction (cough too big to fail).
> Don't build a wooden cottage and expect it function like a castle with a garrison under your command. Even if you slowly expand it to a stone mansion, if you don't maintain a garrison, it won't work as a castle.
Sadly, building an game on someone else's platform is more like setting up a cottage on the land. You might be able to get some farming done and survive, but if the lord fancies the grain, you're out of luck. But also good luck finding land to farm without a lord. Peasant.
Then, of course, legitimacy itself is culturally defined, and in some places being able to depose the monarch would be ipso facto proof of said monarch's retroactive illegitimacy. The notion of "divine right of kings" is far from universal.
Moreover, Gabe Newell always had a controlling stake in Valve ever since 1996, so that prevents any shenanigans. There are comparatively few shareholders (than a public company) and they were all long-term, since Valve will likely never go public, certainly no year soon, or even be privately acquired; while Newell controls it.
In this instance your complaint is about corporate governance rather than tech; (how far back did tech people stop being in control at Sierra?)