This strategy is the opposite of a portfolio play. It is great if your winners stay winners. I think if you are aligned well with the overall market direction that is great.
Basically by only keeping the strongest you should get the highest rate of return until these is a failure. A portfolio play gives you more modest returns but more consistent over time -- you should still trim the losers who do not have potential.
I had never thought of it in those terms before, but this is similar to portfolio diversification in investing. There's the quip that when you're properly diversified there's always something to hate in your portfolio. Of course the flipside is that there's always something to love too.
All that compared to making concentrated bets where you can win big, or lose big.
Basically by only keeping the strongest you should get the highest rate of return until these is a failure. A portfolio play gives you more modest returns but more consistent over time -- you should still trim the losers who do not have potential.