An idea without an execution plan is worthless. Having an actionable plan adds a lot value, which may or may not be realized via an execution.

Ideas are worthless for making money without execution.

Ideas are worthless [snip] without execution. There, fixed that for you.

Some famous physics experiments were thought of before it was possible to execute them. Worthless?

Also how do you execute Socrates' ideas in Euthyphro? Or are those worthless?

There was always an execution. It just happens to not have been the experiment. The reason we know about those ideas is that somebody put a significant amount of effort into telling the world.

I stand corrected

in starting web companies maybe. Not in a lot of other fields, including many fields where the real value is to be created.

I'd argue that creating/creation has a lot in common with execution.