The author makes some valid points. However, I'm not convinced that Pwn2Own is overall a bad thing, for 2 reasons:

1. It is far more public than bug bounties. The browsers that get hacked are in the public spotlight, and that can pressure them into doing a better job in the future.

2. The browsers that put the most effort into security - Firefox and Chrome - did well this year. The article and comments seem to imply this might be a coincidence. There is some element of chance here, so it's possible, however, I don't agree that chance is a major factor. Furthermore, if it was as easy to hack browsers as the article implies, you'd expect all the browsers to be hacked - again arguing against randomness being a big factor here.