Yeah I mean "If I am operating a business and someone brings an idea for something we should do inside that business, the expected value of that idea is close to 0, and for some business it may be negative".
That doesnt say that all ideas are useless. Huge businesses are built off of ideas all the time. Whether it be by accidental timing, cutting edge research, new synergy opportunities or actively spotting a hole that can be filled, the businesses start with an idea and they are not useless for sure.
Once you are up and operating a business however, if an idea is not about something you can trivially do as part of daily operations (continuous improvement has amazing value) but rather is something you need to divert significant resources or attention to in order to potentially realize some other values, then the value of the idea itself, on average, is low, because you will have a lot of these ideas, and you will not be able to dedicate your resources and attention to more than a few of them at a time.
It is far more valuable (on average) to be able to effectively choose WHICH of the already existing ideas have the best return than being able to add another idea to the pile.