This is literally true and goes beyond security. I hope everyone who complained about Google Reader takes note of this; once you have the freedom to modify and rebuild you are trivially able to continue using your software long after the creators have shut it down.
I don't buy this. Unless by slow you mean "heat death of the universe" slow. This is like the "open always wins" argument - wishful thinking devoid of evidence that caters to "If I want it it shall be".
Apple and Microsoft continues to grow. Samsung too, and they have little to no interest in OSS. Let's also keep in mind that most of the world's core services above the OS (eg Google's mail, docs, search, plus) remain closed source, as is the UI layer for most mobile devices (very, very few use stock android.)
Where OSS is doing very well is in commodity infrastructure - browsers, servers, databases, middleware, etc. It hasn't killed the closed source markets there conpletely, but it has made them work a lot harder.
Open-source also means: The entire planet's population is the pool (of developers). And this in turn means:
As soon as there is a real need for something, and somebody in this world is willing to work on it (for whatever motivation), this piece of software instantly becomes available to the _entire_ planet, without barrier (no price to pay, no payment method hurdles).
This is an _extremely_ powerful property which eventually will dominate the nature of solutions we use.
This is all very nice to state as goal, but it does not help if you need money as software developer.
I do a lot of open source on my free time, but that is because I get paid by one of those commercial bad guys companies to work on closed software, which allows me to contribute back for free.
How far do you think most open source projects would be without sponsoring from commercial companies that allow some developers to work on open source projects.
This is one of the reasons why most successful open source software is developer tooling, or nowadays hidden behind SaaS walls.
It is all nice and dandy to talk about open source ideals, but when you need to earn at least 1 000€ per month, those ideals start to fade away. Speaking from experience.
I'm not saying closed-source is "bad guys" or anything like that. I'm just saying what I'm observing: open-source is picking up steam and maturing across the board. It's not slowing down at all. It's true that it will kill some developer jobs. But that can't be an argument for not supporting open-source (tech is always about getting more efficient, resource-wise, and therefor a job killer by definition).
Software in general is 'picking up steam and maturing a across the board'. We now have almost 2 billion consumers carrying a unix box in their pockets, not running open source.
If anything, the relevance of open source is dwindling by comparison.
Useful software takes a lot of time and effort to write, and there is a lot of investment in learning required to get to the point where one can do it.
Unless a person is independently wealthy, a significant portion of ones time and energy must be devoted to efforts that will be paid.
Therefore open source is either subsidized directly by other paying ventures e.g. corporations for whom it is strategic, of it is engaged in by individuals in the time left over after their paid work.
Until the world changes so that people don't need money to live, developer hours will flow preferentially to the ecosystem according to the available monetary rewards.
The ecosystem that makes it easiest for the most developers to get paid will attract the most developers.
This could be the "open source" ecosystem at some point depending on what business models prevail, but I see no reason why it should automatically be so.
I'm not entirely sure I follow your argument, but you seem to be claiming A implies B, where in fact A is true and B is false.
> Open-source also means: The entire planet's population is the pool (of developers).
This is currently true, even when closed source software also exists. Or at least, getting rid of closed source software won't make it significantly more true than it is now.
> As soon as there is a real need for something, and somebody in this world is willing to work on it (for whatever motivation), this piece of software instantly becomes available to the _entire_ planet, without barrier (no price to pay, no payment method hurdles).
This either is not currently true, or is not as powerful a property as you claim.
It does allow many eyes to inspect source code - which is certainly important in developing cryptographic software.
However it currently does nothing to ensure the timely delivery of patches to consumers. Also, usability of open source security solutions is terrible, and unless people understand cryptographic signing, and the web of trust, and build all their software themselves they have no guarantee that their software isn't compromised.
The only thing we can do to improve our situation is to migrate towards open-source operating systems (and software and encryption solutions).