I generally agree, but that basically sounds like prudent investing for eventual retirement. Yes, tune the degree of aggression both in terms of work input and spending restraint, but the "work input" has to be high (and effective) for those few decades.

EDIT: I'm also kind of writing in the context of having your own little economic engine that you own and control, and can be continually running, rather than owning a tiny piece of the abstracted aggregation of an entire economy's engines. That said, dead-simple, low-fee, market-indexed funds are a generally good place to put the surplus fruits of your own little economic engine.