My claim is that equity and fixed income are the important pieces for reaching that goal.

They are, of course, important. The question is whether they are the only important pieces.

What other asset classes do you have in mind

Real estate is the most noticeable thing here, given how for a lot of people it is actually their biggest financial investment (and often highly leveraged, too). Commodities and such generally require paying at least some attention to what's happening and the usual context of financial discussions on LW is the "into what can I throw my money so that I can forget about it until I need it?"