Agreed; most people, me included, would probably be more productive if they interleaved productive tasks than if they did productive tasks in big blocks of time. I was just saying that in my experience, when I'm forced to do some unpleasant task a lot, after a while it's not as unpleasant as I initially expected. I'm pretty cognitively atypical, so you're right that other people are likely not the same.

(This is of course a completely different claim than what the great-grandparent sorta implied and which I mostly argued against, which is that "Most people will break down if they try to work too hard for too long" means we shouldn't work very much, rather than trying to set things up so that we don't break down (through hormesis or precommitment or whatever). At least if we're optimizing for productivity rather than pleasantness.)

Here's a vaguely-related paper (I've only read the abstract):

Participants learned different keystroke patterns, each requiring that a key sequence be struck in a prescribed time. Trials of a given pattern were either blocked or interleaved randomly with trials on the other patterns and before each trial modeled timing information was presented that either matched or mismatched the movement to be executed next. In acquisition, blocked practice and matching models supported better performance than did random practice and mismatching models. In retention, however, random practice and mismatching models were associated with superior learning. Judgments of learning made during practice were more in line with acquisition than with retention performance, providing further evidence that a learner's current ease of access to a motor skill is a poor indicator of learning benefit.