>ReactOS doesn't have a large foundation behind it, and it doesn't make sense for companies to allow their employees to develop and contribute to it on their dime.

It's also a solution to a problem that largely doesn't exist. The people working on it do so for fun, not because they need Windows but not made by Microsoft. The parent comments says "having no alternative O/S to Windows is a real pain" but it's not a real pain to any significant amount of people.