It peaked at 4.05% in March. The last 2 months it went just below 4% as the Unknown category increased. For June the reverse happened, so 4.04% seems to be the real current share of Linux on Desktop as desktop clients were read properly/werent spoofed.
Question: Why is BSD so low? (And why/what is unknown?)
The BSDs got screwed over by a lawsuit in the 90s that made a lot of people hesitant to use them (coincidentally leading to the creation of the Linux kernel). Inertia carried it from there and Linux ended up getting more hardware and software support, which is the primary reason that people pick Linux over the BSDs now.
Less hardware support than Linux without enough substantially better about it to make it anyone’s clear preference. Which isn’t to say it doesn’t have advantages over Linux. Just that the average BSD user is going to be able to easily swallow their pride and run Linux if things went wrong with a BSD install (trust me, I’ve literally done this, these people do exist)