Vanguard target retirement funds have expense rations of 0.08%
Here are 4 common funds that are used in risk parity portfolios:
VTI = .03% VXUS = .06% VGLT = .03% GLDM = .1%
(edit) I am not arguing that that investing in TDFs is inferior solely due to expense ratio cost - the biggest issue is that they lock you in to a specific allocation and re-balancing strategy that might not align with your specific situation.
For most people, it probably makes more sense to recommend something like a vanguard target fund, so that they don't have to think too much about it or remember to rebalance as they near retirement (or actively choose not to rebalance b/c the market is currently good and then get walloped by a crash).
At some point you are being penny-wise, pound-foolish: saving even 10bps (0.10%) on a $1e6 portfolio is saving $1000 dollars per year on management fees. If that kind of difference makes or breaks your retirement plans you have bigger problems (and most regular folks don't have that kind of portfolio, so the savings would be even smaller).
Certainly fees are important:
* http://larrybates.ca/t-rex-score/
but once you're <50bps, there are probably more important factors (like behaviour stuff: not panicking, actually putting money away monthly/regularly (especially in an automated fashion)).
Just saving the time-cost / hassling of rebalancing is worth something, and probably worth the fees you pay for an all-in-one / asset allocation solution.