It is maddening, and puts the burden on people who do try to maintain a reasonable following distance. If you leave sufficient room, there's an endless line of cars that will pop into that space, and now you're adjusting again...in a loop.
So what? If you happen to go faster than the cars that go into the space between you and the one in front, change one lane to the left to pass them. If there is someone in front of you even in that lane, continue at the speed they are driving, leave space in front. Someone goes into the space? Adjust again.
Are you seriously avoiding to leave any sort of space in front of you just because other cars might go into that space? Seems like a dangerous game to play not just for yourself, but for others too.
