One simple assumption for why markups rise with productivity and competition increases concentration.
For those who didn't know (I didn't) IO Economics/ists refers to Industrial Organization. Or so Google informs me.
Inside baseball, I guess.
I’m sorry Brian, but I have to speak out. This has been bothering me every time I see your version of the meme in the article preview, which is about three or four times now, and it’s pained me every time. Pippin doesn’t say “But what about…”. He says merely “What about…” Please amend this so that you can stop doing any more damage.