In your essay, you implied that people were painting alla prima during the Renaissance, that Renaissance painters would start from a rough sketch directly from the canvas, and that they could repeatedly rework parts of the picture.

Let's check. These two paragraphs are everything I've written about the use of oil paint in the fifteenth century:

    It helps to have a medium that makes change easy. 
    When oil paint replaced tempera in the fifteenth 
    century, it helped painters to deal with difficult 
    subjects like the human figure because, unlike tempera, 
    oil can be blended and overpainted. (Taste for Makers)

    What made oil paint so exciting, when it first 
    became popular in the fifteenth century, was that 
    you could actually make the finished work from the 
    prototype. You could make a preliminary drawing if 
    you wanted to, but you weren't held to it; you could 
    work out all the details, and even make major changes, 
    as you finished the painting. (Design and Research)

These are pretty uncontroversial statements. Neither implies that artists started painting whole paintings alla prima from day 1. They say oil allowed artists to work out details and make changes after they'd started. And here is van Eyck doing that ca. 1430:

http://www.escholarship.org/editions/data/13030/d9/ft1d5nb0d...

I didn't (obviously) use Franz Hals to support my statements about the use of oil paint in the fifteenth century, since he worked in the seventeenth. I gave Hals as a counterexample to this claim by you:

    This is not how people painted with oil until the 
    19th century.