You said:
"But I think you will always find a basic scientific made by someone."
I say:
True: Only because a basic calc can be made for $20-$50. PDAs have a long way to go before they get that low. But at $20-$50, you don't get much in the way of a quality calculator.
You say:
"But I will always use a calculator over a PDA device and I suspect the majority of the posters here feel likewise. "
That may be true for you and calculator connoisseur but most calculator users are just that, "users". They only care that it works.
Calculators are growing in size, not shrinking. PDAs on the other hand are shrinking, have more memory, larger screens, in color, and are completely programmable. Further, whatever program you have on your calculator (oops PDA) can also run on a PC, with the ability to transfer files between the two.
It's only a matter of time till everyone stops using standalone calculators. Just like they will for CD players and other consumer electronics.
To put it another way, consider the best calculator that you would like. Now consider that it could be expanded to include phone, PDA, etc. Would you abandon that perfect calculator, simply because it contained a phone? Hardly. We often think of calculators being added to PDA but I prefer to think of an electronic box that can contain just about any program. That is coming.
Some PDAs are now getting about the size of a 15C. Imaging that PDA running 15C software with more memory, program space, color, speed and the ability to transfer programs between 15C and PC. Perfect. Now imagine that with any other "perfect" calculator. It's not very hard to imagine calculators going away.
I have not carried a stand alone calculator for years. I have lots but prefer to use my PDA.
Anyone still use a record player.