You then are the exception to the lane-splitters that I've seen mainly in California where it is legal but also in other places where it is not. Even when traffic is at a "crawl", people change lanes. Most lane changes in this situation are sudden lane changes with a quick glance because the opportunity to change lanes disappears very quickly.
You might not notice as much, the ones who split lanes less, and do so at lower overall speeds, since they won't be passing you as frequently.
Watching driver's head motions helps. I don't push it (much) and try to always leave myself an out. Running with a headlight on during the day helps make the auto drivers more aware of one's presence. One can move the bike around a little side to side, to get noticed faster. A lot of folks are kindly enough to drift over to one side of a lane to make it easier and safer.
Wider trucks, with large side mirrors block the way many times. When that happens I wait for an off-set, or staggered position, as opposed to two vehicles being directly side-by-side. I sort of look for that condition more often than not, regardless.
One other thing I have to look out for --- is other, higher speed lane splitters! Focusing on two or more vehicles in front, others to the side and slightly behind, while also watching the traffic in the two lanes ahead of the vehicles I'm trailing and as much as any adjacent lanes as possible, has frequently left me sort-of plugging the split.
Other riders should thank me at times, for slowing their rice-rocket high speed track bike fat leather padded asses down.
There is a reason for that thick leather in the seat of good riding gear. Any kind of pavement will shred right through blue-jeans, wa-aay before one's body stops sliding, in the event one has to lay it down, which is something I'm rather terrified of doing ON A FREEWAY.