Why is a one way ticket about the same price as a rount trip?

Question

A one way international ticket from Europe to the US costs about the same as a Rount Trip ticket from the US to Europe and back.

Answer 1

Cheap RT tickets have lots of restrictions like no date change
or no refund. If OW is just half of RT, buying two OW tickets
eliminates 'no data change' retriction. That's why OW is set
to higher prices than (discounted) RT ticktets.