The amount of value contained in all the free extensions for Joomla, and in Joomla itself, is staggering if you try to attach a value to it.
The new Joomla Extensions site contains approximately 314 extensions.
A few of these are commercial extensions, so let's use 310.
(the actual number of extensions is much larger than what is listed here, so this is low)
Software developers are paid anywhere from $20/hour to $50/hour or more.
Easily a low average would be to use $30/hour in calculations.
Even the most simple Joomla extension requires 10 to 20 hours of coding and testing.
Some components are easily hundreds of hours (Community Builder).
The average extension represents hours and hours of contributed value.
OpenSEF is already many, many, many hours of work (easily 150 hours +).
Let's use 15 hours per extension in the calculations.
So let's add up a very conservative estimate of the value represented in the extensions listed in the Joomla extensions site.
310 extensions x 15 hours development per extension x $30/hour = $139,500
A ridiculously low estimate of the value of the extensions is well over $100,000 - for FREE.
Let's add the value of the Joomla core development.
30 to 40 to 50 talented individuals contributing hundreds of hours - for FREE.
Let's say 40 people x 100 hours each x $30/hour.
This estimate is low.
There have been more people and more hours than this.
40 people x 100 hours x $30/hour = $120,000
So a ridiculously simple and ridiculously low estimate of the value contained in the Joomla Extensions site and in the Joomla Forge is over $250,000.
A better set of figures may easily exceed $500,.000 or even $1 million in value.
Open source - it does not get any better.