Only a few percent of papers submitted actually get published. There is some amount of work involved. Also, these top journals hire full time editors (former scientists in ther field).

Let’s say it’s 15 papers per month, so $40k * 15 * 12 = $7.2m for four editors. I’m not at all convinced. 40k per issue would be plausible.

I’m guessing that they were exaggerating a bit. I think nature now charges like 12k for open access with makes that number more reasonable.