First of all myopia isn't 'seeing fine details as blurry' - it's nearsightedness - and whatever else this post tested it definitely didn't test depth perception.
And second - inability to see fine details is a distinct/different thing from not being able to count intersections and the other things tested here. That hypothesis, if valid, would imply that improving the resolution of the image that the model can process would improve its performance on these tasks even if reasoning abilities were the same. That - does not make sense. Plenty of the details in these images that these models are tripping up on are perfectly distinguishable at low resolutions. Counting rows and columns of blank grids is not going to improve with more resolution.
I mean, I'd argue that the phrasing of the hypothesis ("At best, like that of a person with myopia") doesn't make sense at all. I don't think a person with myopia would have any trouble with these tasks if you zoomed into the relevant area, or held the image close. I have a very strong feeling that these models would continue to suffer on these tasks if you zoomed in. Nearsighted != unable to count squares.