You seem to be missing the way the website currently works- at least for most of the fares. The OW fares you see are "OW based on RT purchase," as it says there. If you actually try to purchase OW, you will likely not see the same fares.
Cheers.
I know the sale fares often work this way but I'm seeing a lot of
domestic OW fares that are 50% of RT right now.