Any index etf that is at an all time high proves you can hold and make money. Trade the dips, and when you're wrong, don't sell, just hold and wait. You'll eventually go green again. Granted, you won't make money like in the SMX run this week, but you won't lose either.
Study a 50 year SPY or QQQ chart, it's dips, and trade UPRO or TQQQ. See how that works. But don't quit. Follow your rules. Remember, in every 1000% small cap runner, there's lots of losers and bag holders. So stay out.