My relatives, corn farmers in Iowa, have been preaching no-till for three generations now. I asked my uncle why it's not been universally adopted after all this time.
He said it's partly lack of awareness, which was astounding to me. I learned about the loss of our soil and the importance of no-till in the classroom in middle school in an urban area, of all places! The evangelism is occurring, but maybe it's just not reaching the right ears, or it's reaching deaf ears.
The other factor, he said, was that you'll suffer lower yields for a few years after you stop tilling, while the soil builds up a proper layer of decomposing matter on top. Or at least, farmers are afraid that could happen. And it's not a risk worth taking in their view.
There is a role here for government incentives to accelerate the transition. I think they already exist, but they should step it up, since we have been moving so slowly. The government is quite accustomed to tweaking the economics of farming to stabilize such an important part of our society.