While I can agree that many people want more features what does that have to do with 850? So what if it's not good for international roaming- most cell phone users here don't go past American borders. Isn't 850 another feature- an option that many carries do not provide? This is hardly a downfall or short coming.
I would like to see reasonably price quad phones as a standard product. 850/900-1800/1900 but the problem is that most countries are not set up to allow quad phones to work right. Although the demand is there and the companies can make them the providers won't budge to accommodate them.
As for cell phone producers no one makes anything like you would like to see that is compatible with any other system. Most PC/cell phones require special adapters for anything you want to do. Could they make them? Yes.