I don't think that's the correct line of thought "if it's still selling, then leave it that way".
If you can supply your customers something better that they are willing to pay for, why shouldn't you? "Treat your customers well and the business will take care of itself." That sentence is not mine, and it's very true.
A couple years from now, I do expect to be able to buy a better Pandora.
Of course, I don't think they should release a Pandora 2.0 right now. I didn't even receive my Pandora 1.0 and they are already talking about a 2.0? That's not fair to me. So, I think they should ship the pre-orderers, keep supporting them (and learning a lot from the mistakes of Pandora 1.0) and then launch Pandora 2.0 in a couple years, when I'll be more than pleased to order Pandora 2.0 on the very first batch.
I wouldn't expect it to take a long time to take Pandora 2.0 off the ground either. They have learned a lot from the experience with Pandora 1.0, so they will not make the same mistakes, they will be able to improve the process itself and the next Pandora will be ready to be shipped much faster.