yet it's increasingly apparent that their math is "off" since they keep falling behind their competitors.

You don't actually know this for sure because Valve is the only company of the ones you mentioned that actually releases numbers for their games. If you could see numbers for Overwatch, WoW and most Blizzard games right now, for instance, you'd probably conclude that Blizzard is also a company that is failing. When you don't release numbers for your games and your games are losing people left and right your communities can't have these kinds of conversations and you can also mask any issues with paid advertising, which is something that Valve can't really do.

You're essentially saying that Valve should invest more money into making it seem like their games are more successful than they are because other companies are also doing that. This is a pretty backwards and weird argument. In my opinion they should just focus on trying to make good games.