Even if you believe in radical life extension or uploading or the singularity will be within your lifetime it still makes sense, indeed it makes more sense, to save in tax advantaged retirement accounts. Given two accounts into which you can place the same investment, one taxable and one not, by all means pick the non-taxable one. This is investing to maximize your long-term income and wealth potential.

Feel free to keep working and making money at 65. For myself I hope to be productive and active well into my 90s or beyond. But tax advantaged retirement accounts are still the best possible investment vehicle for almost everyone. The only exception I can think of would be someone with a very short time horizon due to illness or something that's going to require a lot of cash fairly soon like a house purchase. If you're planning to live forever, you absolutely want to use a tax advantaged retirement account for your investments even more.