No...this is how you measure performance. If you are paying an active manager like Buffet to manage money for you, you want them to do better than a dumb strategy like "just buy the whole index". That is why relative performance matters here.
This isn't supposed to inspire pity or something. It's supposed to give you information about the possible deterioration of his edge. Which isn't to say that it gives you much information about that, just, that's its point.
What you said here is the equivalent of going to a basketball game and saying that it doesn't make sense to talk about which team was better because they both scored points.
Microsoft, Apple, Amazon, Google, Facebook make up something like 20% of the S&P 500, and most of its gains. Apple and Microsoft are 10% alone.
So you could make the same argument for someone who chose to invest in the whole index, vs just the top 5. Its not necessarily a good argument. It will be interesting if they are still the top 5 tech companies in 10 years. It feels like they have a bit more of a foothold than the Dell, IBM, HP of years past. Maybe cloud vendor lock in isnt worse than the platform lock ins they sold.
