We first estimate the supply-side value by calculating the cost to recreate the most widely used OSS once. We then calculate the demand- side value based on a replacement value for each firm that uses the software and would need to build it internally if OSS did not exist. We estimate the supply-side value of widely-used OSS is $4.15 billion, but that the demand-side value is much larger at $8.8 trillion. We find that firms would need to spend 3.5 times more on software than they currently do if OSS did not exist.

This is the huge takeaway for me. Open Source saves companies and organizations so much money because it allows them to not have to make that component themselves. Having open standards literally saves the economy trillions of dollars not having to "reinvent the wheel".