Thank you Tyler for spending the time to produce the illustration.Even if the 70/30 has outperformed the PP since 2008, eventually you'll run across a timeframe when the 70/30 portfolio falls into that lower band well below the PP. If the relative performance of the two portfolios bothers you now, how will that make you feel?
I selected the PP for its overall stability and risk adjusted return comparable to a more equity centric portfolio.
Unfortunately, I cannot substantiate my decision as the PP has not kept pace, let alone outpaced a 70/30 or even 60/40 allocation on an annual basis since 2008 (10 years). What I have witnessed is the PP gains less or loses less but the increases pale in comparison to an equity heavy portfolio and the losses are sometimes even greater. Case in point, the latest 10-15% decline in equities clobbered the PP as well since Gold was flat and LTT's down 6%+. My 70/30 allocation with International and IT bonds is UP, yes UP over the same time frame with the PP still negative YTD.
In response to your question, I would feel content if the PP out-performed a 70/30 allocation over the next 15 years, but would still contribute to equities as I have internalized that they decline from time to time. I am prepared for that. What I am not prepared for is a portfolio that doesn't offer diversification when equities decline and is muted during a bull market. Lose/lose.