It's a tough situation.
For one, it doesn't matter if apps are optimized or not. It only really matters (for people who care about such things) how a given app performs on a given machine right NOW. Right NOW, the very best high end PCs are faster in general than the very best Macs. We caught up for a brief shining moment.
For two, it is my belief that we will NEVER see true optimization in many key apps. Photoshop, for example, has pacified us with a G5 plugin, but that's a far cry from truly writing that app for a G5, where it would really kick ass. (See this link to see how a G5 can really perform when coded properly:
http://www.apple.com/pro/film/lowry/ ). I suspect Photoshop will NEVER be really G5-pristine. Same goes for the other non-Apple major apps, unfortunately. Remember Altivec? Remember all those fantastic optimized apps for it? Neither do I, cuz they never existed. Apple's own flagship app, Final Cut Pro isn't even 64-bit aware. Yes, it's G5
"optimized", that's a start. Having said that, it's questionable how much benefit one would truly gain with a 64-bit FCP. There's a lot of myth and hype of 64-bit, when really many apps will not benefit at all, or so minimally that it's not worth the trouble. The biggest beneficiary of 64-bit? (according to one online article that I don't have a link for) That's right...games. Great, another reason for PCs to utterly dominate thanks to, of all things, games. Does anyone else see the irony? Macs have historically touted as the "toy", but you can argue that the single biggest reason why PCs dominate in the general buying (non-business) sector is because of games.
Like I said, it's a tough situation. And always will be. I'm just glad that the things I do most (Photoshop and video editing) are extremely fast on the best Mac hardware, so I'm happy. Fortunately, Apple owns FCP, so there's no excuse for them not to make it as optimized as it can possibly be, given enough time. Adobe has no particular incentive to really make Photoshop kick ass on a G5. Apple has every incentive in the world to make FCP shine, and it looks like they're taking that seriously.