rachint@gmail.com declared for all the world to hear...
> Why is that when we get a new network or new technology we need to
> through the hardware & grab a new one.

Because the old hardware is no longer compatible usually.

If you are referring to the recent advent of "3G" networks, they
transmit on a different frequency band to the incumbent "2G networks and
therefore requires different hardware. It's really quite
straightforward.

> I think its because of the new connectivity & new features handset
> manufactures are making a lot of money.

If they didn't make money they would not be in business. A-la BenQ-
Siemens.

> Is there a way that we can reuse the handset more similar to that of
> a laptop where we can add some hardware like connectivties like CDMA,
> WiFi ?

To do so would be prohibitively expensive.

> Is it that the manufactures are against this or this is something not
> really needed ?

Not really needed. The vast majority of the phone buying public want to
regularly change to the latest device anyway.
--
Regards
Jon