This is an incredibly ignorant statement. Have you worked in that profession? Any professional engineering roles?
But that all doesn't really matter because the statement becomes meaningless when qualified with "Depends on the project[...]"
I would be interested in some experiments of average developers learning average plumbing vs average plumbers learning average development. I'd wager theres an order of magnitude difference in the results(time spent, quality etc).
Besides all this incredibility, yes, I do work professionally in an engineering role.
Limiting a statement is not the same as a completely making it meaningless. Of course there are plumbing projects, which are more complex than a static blog. Besides that, I would also like to remind you of the little part of the phrase "I'd wager that". I did not know, that it is an "ignorant" statement, to express ones believes.