1: Regarding your first point. I do believe that Apple could move to an mechanical-less iMac (much like the Air) without raising the price, and continue to earn a hefty premium. Apple would likely use a Samsung 830 given their current relationship with Samsung. Apple wouldn't simply recoup the cost from the removal of the HDD and ODD, they would stand to gain tremendously from the improved reliability of SSDs. Quite a few iMacs fail and require warranty service due to a bad HDD or ODD. The associated warranty burden would (nearly) cease to exist with flash-only PCs. Take a look at the HDD and ODD failure rates on the Air as an example, oh, wait, there are none.
2: You are correct that local storage options will be smaller. If it's any consolation, the storage will be faster.
Anandtech recently wrote a writeup on the 830 and some USB 3.0 devices. While I am completely satisfied with the 830's performance, this first generation of USB thumb drives left me unimpressed. On the bright side, the results do give an indication that there is the potential for the second generation of drives to be extremely performant. Imagine, a 64GB thumb drive for $20 that is double or triple the performance of your current mechanical HDD.
ODDs and mechanical HDDs will be likely be moved to external enclosures where consumers get to choose the features and capacities they deem necessary. Consumers without the need or means for external storage will likely store their data in the cloud.
This is probably how things will play out in the near future. As a technologist, I'd be happy if it happened this year. I can understand why others are resistant, and wouldn't be surprised if Apple held out for another year.