Competition is what drives the industry and has led to the major innovations of the past 40 years of gaming.
The PS2 was a major factor in the success of the DVD format and the PS3 is pretty much the only reason blu-ray was a success. Nintendo surprised everyone with the Wii and introduced millions of outsiders to the world of gaming and changed player interaction forever. Multiple PS3’s can be substituted for a supercomputer. We’ve come a long way since “Pong”.
There were other technical revolutions with every generation of the console wars. Each group saw a weakness the old console one had, and improved upon it.
At any rate it seems impossible to have a “single console world”, at least for now. No one would be content making a game for a console if they knew they could improve upon the system’s design and make way more money. If you want software innovation, it usually follows hardware innovation.
Wait until gaming platforms are so incredibly powerful they can render anything you can imagine, instantly, and with perfect clarity, are functional enough to play any kind game with any interface that exists or might exist in the future, and are affordable, and you might just see the end of the technical arms race.