Now, IBM says "we can make all the chips Apple needs".
Maybe. But this doesn't mean they actually will. Remember, two years ago, IBM told Apple that a 3GHz PowerPC 970 would be no big deal. Jobs promised a Mac based on that chip. Two years ago, the chip still doesn't exist.
IBM's word, at least when it comes to future chip production, isn't worth very much in Cupertino these days.
Apple, and Mac users, have been demanding 3GHz PowerMacs and G5-based laptops for over a year. IBM would have to be both blind and stupid to not see the demand for the chips that these products require. So why haven't they shipped them? Either they can't, or they don't want to.
Jobs said they can't. If IBM is now saying they can, it means that the other conclusion is the truth. Now why would Apple try to maintain their relationship with IBM if IBM doesn't want to develop the chips they need?