I LOVE the idea of a holodeck in 20 years time but doubt that photonic technology will b mastered that quickly that an open and easy to use programming language will b developed
I agree to an extent that as graphics have improved, gameplay has dwindled. However that could potentially change since, as u say yourself, graphics and memory technology probably won't see much of an improvement meaning there is more room for story in games again
My opinion is that as internet speeds and availability increase, along with internet enabled tv's and mobile devices growing in popularity, then all of these will combine to offer an on demand streamed gaming experience.
Playstation, Nintendo, Microsoft will become either service providers which u buy into and receive your content via the medium you choose: tv, pc, mobile device or a dedicated console mobile device. OR they will continue to be the hardware manufacturers of the dedicated (mobile or other) devices and offer the services as mentioned previously.
At the end of the day these guys want to remain in business as long as possible and will try to evolve with the times to do so.
Sent from my SGS