Even if this is true, and it seems much more aspirational than something that actually occurs with any sort of frequency, that's merely one benefit to be weighed against all the disadvantages. To name just a few such: worse average teaching ability than a selection method that focuses on teaching ability, reduced research output due to splitting researchers' time between teaching and research, and of course the issue pointed out in the article that the needs of undergraduate education in large measure limit the number of research scientists.
Were it not for the historical accident that we do things this way, I strongly doubt anyone would suggest we adopt it for whatever tiny educational benefit it may impart to undergraduates -- most of whom won't even go into the academic fields they are studying.
Were it not for the historical accident that we do things this way, I strongly doubt anyone would suggest we adopt it for whatever tiny educational benefit it may impart to undergraduates -- most of whom won't even go into the academic fields they are studying.