The fragmentation argument is very valid. One reason consoles have increased in stature over the years while PC's have slipped imo.
That's the assumed contract you get when you buy a console, "this box will play the games released for it forever".
HOWEVER
I can think of one sneaky little way you could use the upgrade to sneakily shiv the competition.
Put a RAM expansion in your console, for sake of illustration lets use current gen. Lets use PS3. Sony puts RAM expansion slot in PS3. doesnt tell anybody it's plans or what the slot is for. Releases PS3.
One year later, Sony announces 512 MB RAM expansion module. Ships with technical showcase, Killzone hypothetical edition, RAM expansion required. For 69.99, every Killzone HE comes with the RAM expansion. Further, it's available as a stand alone for just 29.99 at any corner store. Even further, all new PS3's sold ship with the expansion, as well as several marquee titles over the next year.
Eventually, you end up with a scenario where almost all PS3's have the expansion, and you begin ignoring the few that dont. It then becomes the defacto standard, and you just one upped the Xbox. Whereas, if you simply announced you ship with 1GB RAM, MS might have matched it, as they did your original 512.
Yeah, sneaky
I should run these companies.
Other companies like Nintendo have done this, but as I recall it's usually near the end of generations, where that console is getting lost in the shuffle of next gen anyway. My plan needs that you do it early.
The one question I have is, is it even technically feasible to include something like a RAM expansion slot anymore?
As I understood it the speed and complexity of the traceroutes now is such it might not even really be viable, all that stuff needs to be on the motherboard and near the CPU and GPU.