It's true that as a motorcycle rider you're completely invisible: not just that you should imagine yourself invisible -- you really are. Nobody in a car has the faintest clue that there can be non-car vehicles on the road, probably next to them when they change lanes, etc. If you think they can see you, you're dead.
BUT I like it that way: it's cool to be invisible, and it's also safer. Car drivers don't understand bikes: when they see you they have all sort of weird reactions -- like kindly going to the side to give you more room, forgetting that there might be another bike on the other side that they are cutting off!
My favorite car drivers are the ones that don't care about me, stay in the middle of their lane at constant speed -- in general, those who are predictable.
And that's probably where the analogy with the startup world breaks: a startup really needs to be noticed to move forward -- although maybe not by everyone; it's better if competitors don't notice you before it's too late.
So cars are competitors; but who are the customers?