Your risk with holding onto your cash until a downtown is that the crash won't be more than the rise. The market will need to crash to below current levels for this strategy to come out ahead.
A lot of people have been waiting for a crash for years. People on 2013 were saying that the bull market couldn't last much longer, and here we are in 2019.
At the end of the day, it's a bet on the market. Personal investment is 80% regret-minimization so make your bet but hedge against it somewhat.