A notable example of how this strategy can fail is the Motorola Q smart phone, which was introduced earlier this year for about $500. Now, Verizon Wireless is offering that smart phone for under $100 after incentives.

"They saw a very high rate of return on the Q because of the $80 minimum (voice and data) service plan that Verizon was asking for," Kort said.

Despite hurdles such as expensive data plans, the analysts agreed that smart phones eventually will be widely adopted. And even when that happens, the PDA won't fade away entirely.

"There always will be guys who need to work on construction or climb up telephone poles who need the larger display of a PDA," Kort said. "There are guys building aircraft fuselages at Boeing who have PDAs on their belt, and when they need to look at a schematic, they whip out their PDA. So there will always be applications."

But those are niche applications. The bottom line is that high visibility moves such as the Treo 680 announcement will not only accelerate the growth of smart phones, but they'll also hasten the decline of the PDA. In the case of Palm, the irony is that it's helping destroy the market it pioneered and built.