I am a software developer, and on multiple occasions I have been approached by an aspiring entrepreneur who wanted me to work with them. They would be the “idea person” with few (if any) defined responsibilities and no strategy or plan. My role would be coding for hundreds of hours for a 50% cut at most. They would present it as an amazing opportunity, then be shocked, if not offended, when I turned them down.
This clearly doesn’t describe everyone who has ideas, but experiences like this can make a person cynical. I am immediately skeptical of anyone who labels themselves some variation of “idea person”. It is almost always indicative of someone who isn’t capable of getting something past the idea stage. On the other hand, I know plenty of successful people with tons of great ideas, but the ability to come up with ideas is never the trait they choose to showcase — to them ideas are incidental.
In summary — of course ideas are valuable. I suspect some (most?) of the anti-idea sentiment has come from a certain kind of type-a “I have ideas” guy that discounts the value of other kinds of work.