@lupyuen Interesting paper, but I think some important facts are overlooked.
To become a competent programmer in the first language, some high number of hours (>1000) are required.
When a competent programmer wants/needs to learn a new language, it is really difficult to motivate learning from scratch and putting in the >1000 hours in learning up front... Which leads to "the shortcut" that is investigated in the paper.

We only have the luxury of learning from scratch once.