Why can't companies provide paid support for open source software? I believe lot of open source products work on that model, including Linux. The bad thing with

Why can't companies provide paid support for open source software? I believe lot of open source products work on that model, including Linux. The bad thing with proprietary software is not many students and researchers from developing countries cannot afford it as the pricing is always based on developed economies scale. But if it's open source, every one can use it and more affluent researchers can get the paid support so they don't need to hunt through thousands of lines of code or fix bug themselves.