>
The article diagrams clearly shows a blind spot for lane splitting motorcyclesNo it doesn't; it clearly shows a blind spot immediately next to your vehicle that can at best hide a cyclist who sticks right next to your rear passenger door, or rear left body panel. (Unsurprisingly: these are the parts of your car you don't see.)
You might nevertheless him or her in the rear-view through the rear passenger window or quarter glass.
Also, you can still see into that area if you tilt your head to the right. That's because the mirror was adjusted that way: to just see the edge of your car with your head tilted toward the side window.
I've always set up my mirrors exactly as this article suggests; I learned that in 1986. Before executing a lane change, I not only look in the rear-view mirror and side mirror, but also tilt my head left. Then just a glance left is required, because the lateral blind spot is so reduced by the positioning of the side mirror that it doesn't require a full head turn.
> A car following closely behind you impedes the rearview mirror.
Yes, a vehicle behind you can occlude a motorcyclist who is riding next to that vehicle. This will be the case even if you drive a convertible with its roof down, and turn your head to face in that direction.
If you tilt your head to the left, you may still be able to see that rider in the side mirror, unless the vehicle behind you is very wide, or positioned to the left.
In such a situation, that vehicle will be blocking more than just a stripe-riding motorcyclist; that vehicle will obstruct a significant view of the adjacent lane, preventing you from seeing a speeding vehicle a little ways back; you'd be foolish to execute a lane change while being tail-gated like that for reasons not related to stripe-riding motorcyclists.
