> I sense that when expectations are clear they'll often surprise you with diligence.

Data does not support your sense.

Most students do not have good time management skills, usually because they have no models and/or have not been taught these skills.

Furthermore, continuous feedback, whether graded or not, has been found to be more effective than one-shot feedback.

Evaluation and assessment is a complex topic towards which many people (not necessarily you) want to take an overly simplified approach.

There are trade offs for any system that is chosen. The organizations providing the grades have to decide what their priorities are (e.g., time, accuracy, etc.).

I'm not sure what public school system has instilled that confidence in you, but it musn't have been mine. I'm also not sure why you think clear expectations about an end of year test will lead to better results than clear expectations about multiple spaced out tests. The data shows that it doesn't.