The problem is that the newest software will not be available for machines that are still capable of running them (from a spec standpoint).
The fact that the G5 Quad won't be able to run this software after being out of production for just over 2.5 years seems ridiculous to me. Especially considering it was mostly PRO users who bought these machines for programs just like this (and not only the current versions when they bought them but subsequent versions). I know this isn't the case for most, but when I buy a pro machine I expect it to last upwards of 4-5 years with upgrades to things like RAM and video cards along the way. It would be nice if companies weren't so willing to ditch their PPC users so fast.
Application developers will follow Apple's lead on this. When Apple dumps PPC support in Snow Leopard, it's the same as announcing that PPC is dead. Developing an app on both architectures is costly in terms of time and resources, and if Apple is no longer supporting PPC the app developers are probably relieved to drop it too.
Apple is a business and they don't care about you or your investment. When the bottom line says that PPC support is no longer worth the resources they're investing in it, that's it.