Good Point. I went ahead and tested this on the S&P 500 cash index going back to 1982 ($50,000 = 1 unit. Add 1 unit after each loss. Go back to 1 unit after a win). There were 3 down years:
1986 : -2392
1989: -854
1991: -111
Long Trades 223
Winning Trades 136
Losing Trades...