I've been thinking about it a fair bit and it just doesn't make sense for Apple to push the "regularly" scheduled launch date for the iPhone to September. It will throw off millions of customers' upgrade timeframes, making them wait long enough and maybe get frustrated enough to go to Android. If they delay anything due to supply issues, I doubt it will be much more than a month long delay. I don't see Apple as giving a crap that people who ALREADY gave them money and signed contracts will be irritated that a new phone is coming out. If anything, the rich prigs of the bunch will just go ahead and pay full price to upgrade again, making Apple even more money. How would Apple see this as bad??
It DOES, however, make sense to stop announcing hardware at a software developers' conference. The added benefit to spacing out the announcements is that it will allow buzz to build, press to be garnered, followed by more buzz and more press, rinse, repeat... It seems likely that Apple will continue with format of the last couple hardware releases and schedule press conferences when they are nearing release date.