Any good reason not to sell all my equities and just put everything in an S&P index?

I'd save myself mental energy of managing my investment accounts if I just sell everything and put it all in an index. Actively managing my accounts with the help of my FA is just costing me in fees, and giving me an artificial sense of having control over my life that has no basis in reality. It's just low-level gambling.

I have equity in 25 different Fortune-500 companies, I'm a little tech-heavy, a few ETFs across various sectors, and 2 larger positions split between S&P 500 growth and index. My risk profile is pretty tame, but honestly, I'm just tired of seeing myself lag behind S&P500. And with the knowledge and research I've gained over the past 5 years investing, I honestly don't even think it's worth trying to game the markets and come out above the YoY S&P500.

Alternative, I could try Dogs of the Dow this year and see how I perform.

Any reason NOT to do this? Any better time to do this than any other time?