Simple ideas like this will naturally occur to many people. A small percentage of those will have the ability to execute on them. A small percentage of those will then actually do so. And an even smaller group will combine it with an otherwise interesting product, thus making it into something.
People often assume that ideas are where value is created. In reality, ideas (even non-simple ones) are plentiful, easy, and often generated by more than one person at the same time. Ideas are essentially worthless. Value is only created when people actually make stuff.
See also: patents (which protect the worthless part of this equation, and thus make it harder to do the truly valuable part).
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