'Sometimes I wonder if once long ago there didn't really exist wee folk(fairies, elves, and such) and we lost the ability to see these.'
I don't doubt that these wee folk still exist...but as you say, we've lost the vision.
Do you ever catch something out of the corner of your eye & when you turn your head to look, nothing's there? When this happens to me, I greet whomever was crossing my path and invite them to come closer.
I'll share a secret with you. Whenever I walk the woods, I anticipate meeting myself on the path coming from the opposing direction.