If lots of different people find an insight interesting and true, then it might be game-changing.

This is especially true when a large diversity of thinkers who don't often agree agree.

If everyone finds it interesting (that is, novel, surprising, not just "well duh") and also true then it's a very good sign it's onto something deep.

The logic is similar to Fil Menczer's observation that early reshares of a piece of content from very different people is a good indicator of how virally it will spread.