I'm quite skeptical on multi-decade future projections. You heard it before: Past performance is no guarantee of future gains. So when reading something about a X%/year average return, you simply can't project that into the future. The future may be entirely different than the past. Economy may stay in a depression your whole lifetime - then what?

I think all investing - that includes planning for retirement - involves being active and staying informed on important trends and developments. From my point of view it's safer to it that way than trying to rely on passive income from funds.

ya.ya.yo!