Pretty sure he could if he got to practice writing crud apps for a month beforehand and the apps were no more complicated than what a mediocre engineer can write in a week.
Also, one engineer making 10 crud apps would probably share a lot of code between the apps. Which would allow him to make the new ones even faster. And the result would be easier to maintain.
If you instead hire 10 engineers to write 1 app each, you often end up with 10 apps using 8 different frameworks in 3 different languages. And then you will need 10 engineers to maintain them.