But all you need is a bull market to 50-100x your money with 3x funds https://i.imgur.com/PF7XEaR.jpg
If 7/10 past decades are a bull market then odds are you will make good money.
Market neutral strategies are different though.
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https://www.wolframalpha.com/input/?i=3000*%28%28integrate+1....
A calculation i ran to answer this problem shows that if you have $10k and split $3k of into cash that yields 3%/year and the $7k is put into TQQQ, which generates a long-term CAGR of 53%/year, approximates the actual returns of TQQQ .
So this turns the $10k into $1.5 million over 12 years, which is close to the actual result (100% or $10k invested in TQQQ at the start), assuming a crash happens every 8 years (modeled by exponential distribution and based on empirical evidence going back the past 100 years) and and then after TQQQ falls about 70% the $3k cash is then put into tqqq. After crashing, the above formula assumes that TQQQ races higher in order to maintain it's long-term CAGR, so buying the dip helps a lot.
So generally speaking, keeping 30% in cash/bonds equals the result of 100% fully invested if you buy the dip. The downside is if there is no crash you will lag.
There are various tweaks like above to improve risk adjusted returns. It's not that hard to do if you have a basic knowledge of calc and stats.