Apple will try to hold out as long as it can. I remember during the PDA days, people were still buying black and white Palm Pilots even though ipaqs were more powerful. Of course, eventually Palm was completely wiped out.
Apple is not Palm, it will be around for a long time. As for Palm, I had $9,000 in Palm stock almost wiped out in a short period of time. Not completely, it became worth $1 to $2 total. Funny thing is lots of people were buying Palm devices as the company went under. Apple is a stable company, and the stock price will eventually go up again.
Now Blackberry is getting wiped out. Apple isn't Palm, but I think the loss of Jobs will have a negative effect eventually.