You cannot walk 100 miles in a day, but anyone with a bit of training can cycle that in an afternoon. It's not a matter of effort or laziness, it's simply not possible.
The stitching comment is just pedantic. People don't hand stitch like a machine not because they are lazy, it's because it's ineffective and impractical. It's not impossible to drive screws directly into softwood by hand, but you'd never get anything done that way. It's not lazy to choose another method, it's just being an effective worker.
As for coding agents, it's clearly effective to write software without them because we have been doing it for decades so far. It still remains to be seen whether they are laziness (ie. it's just a motor) or if they are actually enabling new possibilities (ie. we get software that really wouldn't have been possible before).
Can you write 10k LOC a day without a coding agent?
It's the same issue. You can walk 100 miles. Just not in a day. And you can create 10k LOC without a coding agent. Just not in a day.
I don't think that coding agents enable technical possibilities. They just allow things that wouldn't be economically possible without them.
Minor nitpick with your first sentence: I do not believe "anyone with a bit of training" is an accurate way to describe what is required for pedaling a bicycle at 20 mph for 5 solid hours.
At a time when I was in better shape than the average person, the most I ever worked up to was 40 miles, and it was brutal. In my entire middle-aged life, I have met exactly one person who believably claimed to have done 100 miles in a day. I'm sure it's easier than many/most people think, but not 'anyone' easy, with just 'a bit' of training.