I understand that buying and holding a leveraged S&P 500 ETF such as UPRO, due to compounding returns, leveraged ETF values tend to decay over time relative to non-leveraged ETFs in volatile markets, but everytime a back test buy and hold strategy for any leveraged etf the return are impressive:

UPRO from 2011 + 505,58%

TQQQ from March 2010 + 948%

even including 2008 bear market

SSO  from July 2006 +86,33%

while SPY return since Dec 2006 is +50%

So what I m missing? It is very clear that lavaraged ETF have a great drawdown and have big drops, but it still seems worth the risk if in a bull market I can make a 500% return.

Please any advice is welcome.