Why do I need an Intel Processor to use Steam with a Mac?

I own a Powermac G5, which is certainly fast enough to use high performance games like Crysis. I just don't understand why it's so important that I have an INTEL Processor. I was also wondering if there will be a release of Steam that doesn't need an Inter Processor and if there is a way for me to use Steam without an Intel Processor on a Mac.Why do I need an Intel Processor to use Steam with a Mac?
Because Intel processors run newer versions of Mac OS X natively and Power processor only virtually therefore Steam developers decided they would not support Power processors.
They did not want to loose their time on something that will be very soon extinct.
The moment Steve announced move to Intel Power Macs were history and developers do not want to support them any more.
There is just no way neither they nor anybody else that comes with new game engine will support Power Macs. You will have to move to Intel Mac.Why do I need an Intel Processor to use Steam with a Mac?
Sigh...no, there will NEVER be a release of Steam for the G5. There is no possible way for you to use it. End of story.

The G5 is OLD. It's 5+ years old. Even if it could run Crysis, it would choke on all but the lowest settings. Do you have any idea what a pain in the butt it is to maintain a codebase across two different CPU architectures, especially when the PowerPC CPUs will never get updates and Apple has already abandoned them? Blizzard recently cut PowerPC support from WoW because they couldn't manage to work around bugs in the graphics drivers in 10.5.8 for PowerPC Macs to keep feature parity. The best video card you could get in a G5 was the 7800GTX, and that was only on the last G5s they made. That's a low-end card by modern standards. Your G5 is not fast. It is old and current software support for it is virtually notexistent. Get used to it because it isn't going to get any better. G5s aren't getting any younger. There is zero point in putting in time and effort to develop for what is a dead platform. Apple abandoned them. So is everyone else.Why do I need an Intel Processor to use Steam with a Mac?
Because the PowerPC processors, while they are very good and could certainly run the games, are outdated, and don't support the newest version of OS X, which steam needs to run. Also, since the games are based on the same engines that run on the PC platform, just ported to use mac technology, they won't run on the older non Intel Macintoshes. Also, so everyone makes more money.
Everything the others say is important, but has nothing to do with why you can't use those apps (games are apps). It isn't your processor that severely limits the games performance. It is the development of the game that totally ignores the PPC processor. There was a common saying in the early days of TV broadcast (1940s-50s) for poor picture quality: "It isn't us. It's them," to say it's the TV station that is at fault. For Steam, it is them that limits your use of the G5.

To use an app with both Intel and PPC, the app must have code written for both types of processors. You can't develop the game with only Intel code and that lets it run on a G5. It must be developed for both types of processors. The developer doesn't want to spend a lot of time doing that. Also, it would mean either the game would be much larger or there would be two versions of the game.

Retail DVD versions of Mac OS 10.4.6 to 10.5.8 had code for both Intel and PPC processors. If you had an Intel Mac running Os 10.5.8, and you installed OS 10.6, your HDD suddenly gained about 7GB of space. That's because OS 10.6 lacks all PPC code, so it is smaller than OS 10.5.8... and Apple can develop it much more quickly, saving themselves time, and saving the customer money (OS 10.5 cost $160, OS 10.6 cost $29).