On another note, anyone that doesn't think API design is a creative endeavor and worthy of protection probably has never made a great API before. It may be OK to accept that and also let other people use the API for free but I think ruling that it isn't is BS.
Like, “how many ways can you do a date api”, and then turn around to look at the original java Date api, the Calendar api, JodaTime and JSR310.
Maybe the fundamental properties of the universe aren't copyrightable/trademarkable/patentable, but what you CHOOSE to do with those - what API you design or what widget you build out of it certainly is.
So if ReactOS gets popular but doesn't support Windows 10 APIs, will it be harming the windows ecosystem? If popular implementations of a tool exist that don't chase other (official or not) implementations' features but still get lots of users, that probably means that the popular implementations provide other benefits.
> API design is a creative endeavor
I agree with that.
> and worthy of [legal] protection
But not that.