Saving for retirement makes sense even if you don't expect to retire provided that you can access the retirement funds for other purposes, and that the laws of your country are such that this is still an advantaged position. In the United States and some other countries, saving for retirement is investing to maximize your long-term income and wealth potential.

Saving for retirement makes more sense, not less, if there will be radical life extension. Do you want to work for 650 years? or work for 50 and play for 600? (Feel free to define "play" as choosing more fulfilling but less lucrative work.)

Most importantly, saving for retirement makes a heck of a lot of sense if you don't place 100% certainty on uploading or the singularity by the relevant date when you'd otherwise retire. Or you aren't sure the singularity will actually eliminate the need for money and capital. For instance, what if uploading is possible, but costs $2 million a person in 2013 dollars? A magical singularity genie that grants everyone a cycle of infinite wish spells would be awesome, but it is not a retirement plan.