No I cannot explain why they do such stupid things and it's beginning to hurt them.
The request was to explain why PC is a direct competitor. But again you know more than Sony and MS with hard numbers and market research they have access too aswell no doubt.
My best guess would be they still think PC gaming is stuck in the same place it was in 2005, where it really wasn't a direct competitor. . .
Or they have access to hard numbers and market research indicating it's not the same thing. A platform growing/shrinking doesn't correlate to causality, but lets just roll with whatever theory suits the agenda. And to forstall the "both in the same boat", no my argument is that they do treat it differently (which is an observable fact) and they have their reasons. So the onus is for the other person to show otherwise.
For example Titanfall (and some other games). Have you seen it? It's timed first on both PC and xboxes. If MS saw the PC as a direct competitor on the same scale as PS4 - actually they should treat it as even more of a threat because it has a keyboard/mouse, better graphics, no paywall and a bigger install base - they wouldn't let it near the PC, at least not before letting it on the PS4 which would be the wiser of the two options if we take into account things like the PC install base being much bigger off the bat.
It's quite obvious they see the PC port as not direct competition and this is in 2013 not 2005. You may think they should, but I have yet to see any compelling reason.