This is frankly wrong. Performance comes in multiple flavors. Latency is one of those, and there we know that percentiles really matter (see Andrew Certain's section of this talk: https://www.youtube.com/watch?v=sKRdemSirDM&feature=youtu.be... for Amazon's experience).
But for others, like throughput and scale, you don't need to know the distribution. In fact for throughput, the only thing that really matters is the long-term mean latency. For concurrency, it's that and long-term mean arrival rate. I wrote a blog post about it a while back (http://brooker.co.za/blog/2017/12/28/mean.html).
The core point here is that all summary statistics are misleading. You need to be clear on what you care about, and making absolute statements about the mean isn't a good way to do that.
Edit: This came across a bit more confrontational than I had intended. The OP makes some good points, but I think his point about the mean is overly broad.