Is this a fair description of folk ethics?

No, because we don't even know (yet?) how to formulate such a description. The actual decision procedures in our heads have still not been reverse-engineered, and even insofar as they have, they have still not been explained in game-theoretical and other important terms. We have only started to scratch the surface in this respect.

(Note also that there is a big difference between the principles that people will affirm in the abstract and those they apply in practice, and these inconsistencies are also still far from being fully explained.)

But you at least need some kind of feedback. "QALYs per hour of effort" is pretty decent.

Trouble is, once you go down that road, it's likely that you're going to come up with fatally misguided or biased conclusions. For practically any problem that's complicated enough to be realistic and interesting, we lack the necessary knowledge and computational resources to to make reliable consequentialist assessments, in terms of QALY or any other standardized measure of welfare. (Also, very few, if any things people do result in a clear Pareto improvement for everyone, and interpersonal trade-offs are inherently problematic.)

Moreover, for any problem that is relevant for questions of power, status, wealth, and ideology, it's practically impossible to avoid biases. At the end, what looks like a dispassionate and perhaps even scientific attempt to evaluate things using some standardized measure of welfare is more likely than not to be just a sophisticated fig-leaf (conscious or not) for some ideological agenda. (Most notably, the majority of what we call “social science” has historically been developed for that purpose.)

Yes, this is a very pessimistic verdict, but an attempt at sound reasoning should start by recognizing the limits of our knowledge.