First of all, this isn't necessarily an either/or situation, if Nokia's latest internet tablet interface is anything to go by, the S60 touch interface will give you the option of entirely using your fingers or the stylus, or a mixture.
Secondly, some people say stuff like "Nokia's got to change their interface because they're losing to Apple", but this just doesn't match up to reality. Nokia's market share is 40%, but Apple's is somewhere below 1%. Nokia's profits are going up in every department, but Apple has yet to make any money from their phones. Beyond the media hype, where is this triumph of Apple?
The truth is that the phone world consists almost entirely of cheap phones, and the features that do best are the ones that are available on the cheapest models. Apple doesn't sell any cheap phones, so they have almost no direct impact on the phone world. Apple might influence the design of others, and others might influence their design too, but in terms of consumers very very very few of them will be buying any of Apple's current products.
Apple hasn't sold very many phones yet, their achievements have been in hype rather than sales. And at the prices they're charging, I don't think Apple have any intention of selling large numbers.
Nokia's position is totally different, they DO sell a lot of phones. For every Apple phone sold, there are 50 to 100 Nokia phones sold. A LOT of people are used to the Nokia S40 and S60 interfaces, which seem to be converging into one. You can't just abandon an interface which is so widely-used, because you will risk losing the customers you've got. The answer is to evolve the interface rather than totally replace it.
Thirdly, there's nothing wrong with a stylus!
Apple basically just wanted some bit of hype to make people think they'd reinvented the wheel, so they started spreading this "stylus bad, finger good" idea around the place and the media started accepting it without any critical thinking, like so many other things about the iPhone and Apple's products.
I've got two Nokia internet tablets, some of the apps are finger-based and some are stylus-based, and there's not really any practical drawback to the stylus ones.
Even on the web browser I preferred being able to just point directly at a small-sized link without having to zoom in first.
I've also had a Nintendo DS in the past and the stylus is excellent for gaming, it allows very precise movements.
There's the old chestnut about what do you do if you lose a stylus, but as they only cost a few cents to make that can be solved by including plenty of spares with the phone, and by offering free replacement styluses at all points of sale.
Apple did that very right. A pen is nice for drawing and sketching, bit of note taking on the quick. But that's all.
...so you think people shouldn't be able to take notes or draw pictures on their phones? You want to dump those features completely?