Because.

The reason that people "don't see x" is that they're seeing 'y'.

They "just don't think" whatever it is we think they ought to be thinking; they "don't even think about" whatever aspect of things we consider most urgent, obvious, and clearly illuminating -- because they're too busy thinking something else about other things entirely.

Your ideas, even my ideas, could be wonderfully helpful to a great many people.

They don't want them. They have theirs.

And look how well we're all doing!