Beyond complaining about late code releases, he also says this:
Open source is a great way to spark or accelerate momentum. It’s a terrible way to reverse a product’s decline.
Open source, in other words, is all about what's new. It's about challenging established products, not propping up the dying.
The key word here, I think, is challenging.
Most of the best open source projects challenge an established niche. The Firefox browser. The OpenOffice.org office suite. Drupal. Android. Apache.
In all these cases there was already a product category, and established leadership within that category. Without open source, the natural forces of market consolidation, combined with the human cost of building a code base, would have resulted in a monopoly.
Instead companies and/or individuals got together and built a challenge to that order, either resulting in a single challenger or (as in the case of Eclipse and Apache) multiple challengers. This reduced the monopoly rents of the market's winners, with most of the benefits going to users.
Symbian, by contrast, was the monopolist. Back in the days of Real Time Operating Systems (RTOS) Symbian was absolutely dominant. Nokia was the cell phone leader, and its competitors all used Symbian as well.
Unfortunately, Apple obsoleted the whole category. Phones are being replaced by mobile Internet devices. Symbian wanted help in making the product transition. There was no reason for anyone to help it.
Even Nokia is no longer interested in Symbian. Its interests going forward are Qt and the Meego platform. It's going to have to make its own product transition.
Open source can't cure a product death spiral.