Nah, I invest in separate companies as well. Just that the index's paint a broad picture of the health of the market just so people don't think I've cherry picked. Guess we can revisit this in another 18 months and see how Tesla performs.
Well, you know what they say, "past performance is no guarantee of future performance."
I don't see the value in comparing individual stocks to the market as a whole unless your strategy is to spread the risk (which is a fine strategy) by avoiding individual stocks. I am sure that I could take any of your top individual stocks and compare them unfavorably to the S&P over some period of time in the past. That time is now for Tesla compared the past year or so, but had you gone back a full two years, Tesla would have outperformed the S&P. In either case, it helps very little in projecting future returns.
As I am sure you know, the S&P and other index funds provide decent returns, but they will never be able to match a stock like Apple, Microsoft, or Amazon once they take-off. I get that you do not believe Tesla is akin to those companies, but showing that the stock has been flat (compared to an index) says nothing about Tesla's future potential. Using that standard, you would have been advising people to avoid Amazon stock back in 2014.