Re: "every closed source software vendor has their own license usually with onerous restrictions"
The difference between closed source and open source is who has the authority to make modifications. With closed source only the vendor can make changes to the code. So you are completely at their mercy if something will get patched or added. With open source, you have the explicit authority to make any change you want for any reason. Whether you do, is your choice.
From a practical user perspective, there often is very little difference when using either if the code is being used internally. If the code is being used externally then the license restrictions do matter and often the open source licenses are less restrictive by default as you being able to include the code in your code base. With closed licenses, one needs to read the T&Cs to be sure though many cases you can include a compiled binary in your code.