That is what I've concluded - the KISS principle is what makes certain hedge funds and investment managers outlast the crowd. Years ago I worked as an analyst at a fund of funds where we would interview hedge funds to give them allocations. Many of these firms were quant funds that had or were a team of Phds with the most convoluted models imaginable. After all these years (about 20 years now), I would say 90% of those firms no longer exist. The ones that do still exist are the ones that had more simplistic strategies that could be explained to a grandmother. These firms tended to have much lower sharpe ratios (of around 1) than the flash-in-the-pan complex Phd quant firms.
That's not to say that Phd quants and low sharpe ratios are mutually exclusive. Take 2 sigma for example. I believe they have a few hundred Phds on staff but their fund offerings have a sharpe of around 1. So its safe to say that the Phds are merely window dressing. If these firms had some magical insight, why are we not seeing trillion dollar AUM firms?