When some random relative tells you they have a great idea, and it's simply a punchline, that's what is worthless. That's different than when someone with extensive domain experience tells you they have a great idea, shows you they've put thought and research into it, and can articulate why it's better than other things out there.

Afterall, if ideas were worthless, wouldn't having a biz co-founder with domain experience be worthless? Or, really, for hiring anyone to do anything? Experience is important because it helps us recognize what is a bad idea in the given field, allowing us to save precious time on execution.

Execution seems little more than the filtering of good ideas from bad ones that you didn't know were bad.