Start-ups like Cloudability are giving top managers great visibility into their cloud costs, meaning the word on public cloud economics is out. Private clouds can't match it. Some groups, like the U.S. Department of Defense, will always need private clouds for security, and their efforts in cloud are all about that, as GCN notes , but most enterprises have different bottom lines than your average general. Depending on public clouds to do their own security, despite the risk, is the economical bet. One thing I learned about open source early in the last decade is that its benefits tend to fall most heavily on users, on those who commit to the software, rather than on those who create it and try to make money off it. Cloud is the first computing revolution for the era of open source, and it is beginning to look like it will follow this path of open source economics where the users win and the builders lose. At the time of publication the author had positions in INTC, MSFT, IBM and GOOG.Follow @DanaBlankenhornThis article is commentary by an independent contributor, separate from TheStreet's regular news coverage.