Why Playstation separating from Sony is necessarily a good thing.

[mine]

No. Not at all.

The Playstation division can use the resources and talent of the other consumer electronics divisions. It is no easy task to design good hardware - take a look at the much bulkier XOne.

As soon as such designing experience isn't needed anymore the Playstation brand has to go "virtual" or will vanish. Because everybody will then be able to use some PC-hardware (maybe an NVidia, AMD or Intel reference design) and sell it as an settop box or console.

At this point the OS is "king". Microsoft has no problem selling a "Windows for Games" reassembling the XOne experience as the XOne is already running Windows.

As soon the Linux based Steam OS or Amazons Android based consoles gain enough market share Microsoft will counter them.

Sony can't as they neither have the experience nor the resources to get their OS up and running on generic PC hardware.

The new generations of GPUs will soon make the XOne and PS4 look even more outdated as they are already. It is just a matter of time when the "real" Next-Gen hardware will become affordable to the console customers.

Expect this to happen within 2-3 years.

Microsoft and Sony knew this when they decided to go the "cheap" route. This generation offers the least amount of power for the money compared to the PCs when launched. And both are not that heavily subsidized as the lifespan is expected to be much shorter then the previous generation one...