I think that's the crux of it. Somebody could monitor all the various news sites and spend an hour a day here posting comments and stories and so forth, but I suspect most folks would rather spend that time doing something else.
I tend to post in bursts, so most of my karma comes over periods of a week or two when I'm posting several times a day. It's actually a bad sign, because it means I'm not working on my startup. ;-) Then there are periods where I'll post like twice a week and my RescueTime log'll show that I'm spending like 80-90% of my computer time coding. So yeah, it's a tradeoff, and ultimately the code is more important, but I find that I burn out if I spend too much coding.
I think that's the crux of it. Somebody could monitor all the various news sites and spend an hour a day here posting comments and stories and so forth, but I suspect most folks would rather spend that time doing something else.
That said, edw519 is a pretty cool guy.