If we look at this in a strict sense then those are implementations as well, just theoretical ones.
I consider a scientific pager, a thorough technical specification or a rich, well-structured design document not 'just' ideas anymore. So in a sense those examples actually don't relativize your point, but strengthen it.
Ideas are usually much more vague, they point in a general direction. Another interesting fact about them is that they are often incremental, small and pragmatic, but they are just as much ideas as the big, exciting ones.
Smaller, more practical ideas are my personal bread and butter. They also need to be taken apart, composed into a sound plan and implemented, but they don't ask for much.
The idea might potentially be interesting in itself, but without the implementation it won't be all that useful.
Mainly though it’s through the act of attempting implementation and interacting with the world that you learn the most. Someone who refuses to try to do this to get better probably just isn’t very capable and their ideas probably aren’t very good.
Even if you do come up with an idea that is viable most of the time so have others and it’s the successful execution that sets you apart.
I’ve met people that sit around patting themselves on the back for having the same idea that someone else used to actually build something.
While having the insight is critical, it’s a lot smaller part (also usually their idea was a vague generalization of whatever ended up existing).
Kind of reminds me of how the Winklevoss twins were portrayed in the social network, no idea how true to life that is - but that sense of ownership they had when they didn’t really do anything of value.
I just reject that ideas are worthless. I share all my ideas online because I think they have value. I want people to steal them because I want the outcome of the idea: I want the idea's implementation to exist in the world for me to use. Some credit would be nice too of course.
Ideas have value, and someone who can unite people with a clear vision can do incredible things but the implementation is a big part of the actual difficulty and usually you have to update the idea as you learn more from the implementation.
In general I suspect the implementation is usually harder than coming up with the idea in most cases and fewer people can do it. (Exceptions might be things like General Relativity and initial Bitcoin paper).
Still, obvious value in trying to come up with things from first principles.