Asset values can go up AND down. Ignoring the idea that your asset can decline in value can lead to faulty analysis and results. If Microsoft mismanages its subsidiaries, then it's very easy to see their values decline, just look at Disney and ask about the value of Marvel Entertainment today vs its value right after Endgame came out and smashed records.
Yup. And even ignoring that Microsoft paid more than market price for the shares due to the nature of the acquisition, just because Microsoft spent 70 billion on Activision doesn't mean it's equivalent to a straight balance transfer into an equivalent valued liquid investment. There has to be willing buyers.
I've read that Sony paid 100 million for Firewalk and if that's accurate then according to some people's logic it must mean that Sony is still sitting on what's equivalent to 100 million dollars.