These are the 10 year returns I’m seeing according to S&P:
S&P 500: 11.1%
S&P 500 Top 50: 13.2%
S&P 500 Top 10: 18.1%
The trend is pretty clear, at least in the last decade. My other point was that the historical data may not be as relevant because the index is much more top-heavy today, perhaps in part due to the popularity of index funds and part because the top companies are actually outperforming.
Here’s an article to that effect - the top 20 stocks in the S&P accounted for ~90% of the index’s gains last year: https://www.visualcapitalist.com/cp/top-20-stocks-sp-500-ret...
To your question about picking the extreme Top 1 stock - again I’m having trouble finding good data on that, but I’d be curious what the hypothetical outcome would have been over the last 20 years.