Lets start with voxels. Everyone knows what a pixels are, right? For comparison, pixels are dots in
2D environment. Now imagine pixel, but in 3D. Thats voxel. You can see them as atoms in future games. Smaller the voxels are, detailed the model that its made of becomes. In future, we can see infinite details in our games. More RAM and more processing strength assures much more better graphics then on todays machines. Voxels will also allow much more better physics in all games.
You can look at it like this; Loooong time ago, when Pacman arrived., it was played on huge computers and, back then, those graphics were considered "great. Now the same game is played on our mobiles with graphics that are, well, not so great 
. You can see the same situation happening over and over again in the past, present and future. So, basically, we will be able to play Crysis on a mobile phone.
So, thats for the graphics.
MMOs. Most updating games on the world. Every second "Patch 1.0.0.1, Patch 1.0.0.2....." That will also come to the new level. Do you know the fact that machines as powerful as human brain will be available for 1000$ by 2020? Do you know that same machines will cost no more but 20$ each by 2030? Now you do! Imagine games where humans are not its actual developers. Imagine a machine creating games around the clock much faster then human? Thats the future. MMOs, possibly even other games, will be infinite. Its something like this:
You are a player who played WoW for most time. You hear that max level is 100 and that latest zone is "#$""#%$#". You come to that zone and lvl up to 100. Then you realise that 100 is not max lvl and that "#$""#%$#" is not the the most difficult zone you can visit. All the sudden you see all new zone called "$#%&#%" and that max level is now 110. This is a process that repeats all over again.<br /><br />So, every game will be infinite. If we do some calculations, we can see that machines as powerful as about 50 human brains will we available by 2030 for 1000$. Yep, cheap sh%t <img src='http://public.gamedev.net//public/style_emoticons/<#EMO_DIR#>/smile.png' class='bbc_emoticon' alt=':)' />.<br /><br />With more powerful information sharing technology, games will not sell in those expensive boxes anymore. We will be able to download them instantly and play them, again, instantly without slow installations and HUGE downloads.<br /><br />Any thoughts?<div> </div>
What do you mean by "as powerful as the human brain", how can one quantify the power of the brain? And even if you could how can you guarantee that the current rate of hardware improvement will continue? Haven't they pretty much reached silicon's limit? All they can do now is improve processor architecture or increase the number of cores, but that in itself will have a limit.
Also, why should all games be infinite? I doubt every game needs to be that large, because just because the world is infinite doesn't mean that there is interesting stuff to do everywhere. If you want an infinite world you need to make it interesting for the player to explore. What about simpler games like plants vs zombies?
Would you mind linking to some of your sources backing up what you say?