My question is: In the future (lets say 5 years time), would you ever modify the game in such ways as well as the minimum requirements or will it more or less stay the same? After all a computer that's 16 years old is beyond obsolete right? I can't even think of anyone who has managed to keep a computer going for 16 years.
You wouldn't believe how old computers people have and use, not to mention companies. It depends mostly what the computers are used for. Quite recently I did some maintenance on a Windows 95 rig, which served as a typewriter. A few years ago I was asked to find working 486 PC's for spares. They were needed in a factory for driving dedicated production related programs. Recoding would have cost tens of thousands, replacing a broken PC only single hundreds of euros including the work. So a well kept computer of today would run AH fluently after a decade, but only the version of we have now.
Having hung along for over a decade I can say that AH changes very slowly. During this time the minimums have come up somewhat, I recall the reference rig used to be a Duron 750 based one running Win98, now the minimum CPU is 1.8 MHz running XP. You can get better rigs for free from companies whose storage rooms are full. I recently demolished a dozen of P4 2,4 MHz desktops for a customer, there's no aftermarket for such any more. After all, the Pentium4 Willamette 1.8MHz was released already in 2000, so the minimum rig is about twelve years old now!
I've read one reason for keeping the requirements low is the enormous popularity of cheapish laptops people try to play with. Entertainment is becoming more and more dominant in all home computing, so I guess and hope in a near future (your five years span) even the Intel graphical circuitry will be able to run today's games or at least AH with a high eye candy level.