I'm mystified by how many major sites have terrible usability issues on mobile devices that are used widely. (older iDevices cheap-mid level Android phones). A

I'm mystified by how many major sites have terrible usability issues on mobile devices that are used widely. (older iDevices cheap-mid level Android phones). Are the proprietors of these sites, which live and die on their traffic, actually unaware of how bad the experience is? Or are the proprietors oblivious because they always have the latest iPhone or Galaxy? Are the developers oblivious too, or are they keeping their bosses in the dark? Or are the business requirements for the sight so absolutely needed, and it is simply hard to make it work? Anyone able to venture a perspective on this?