In combination, well, that's passing behaviour. It's never that they can't see you or need to be told. It's like the people who ride around after dark lit up like Vegas. Trust me, it's not that people couldn't see you, they can see a bike with a single decent light well enough, it's that for whatever reason they've constructed they simply don't care or aren't looking.
Agreed. Drivers approaching from behind are scary, but in the absence of serious Weather, they generally see you just fine. Cyclist 'invisibility' is more of a factor at junctions, where they're looking for cars and seeing A-pillars. And most of the time they'll still see you, but either underestimate your speed or decide that as the driver of the more important vehicle they get to bully their way out.
Putting yourself where they're expecting cars to come from helps. Being interesting-looking can hold their attention for long enough for them to get a better idea of your speed, and maybe make them more interested in getting a decent look at you than getting there first.
FRIKKIN LAZERS might wake them up in a small subset of conditions. But mostly it comes down to whether they bother to look, and no amount of space lemon tactics will help with that, all you can do is anticipate them failing to see you and react accordingly.