Hussar
Legend
I'm not sure if this was directed toward me (or if it was just thrown out there in particular), but I'll admit that I don't know; Teos Abadia may have drawn some conclusions in that regard, but I honestly can't recall off the top of my head, though to be fair that's not really germane to what I've been discussing here.
Little of both?
My point being, there is a huge difference between sales growth slowing and sales outright falling.
We know that sales were falling for 3.5. It wasn’t that they were stable or the rate of growth was slowing, sales were outright dropping.
The only way to stay afloat was to keep endlessly churning out another book. And that isn’t stable. It’s just not because too much rides on those initial sales of each title.
The slower release means that you aren’t taking sales away from the tails of older books. That’s the secret to 5e’s success afaik. That you have six or eight year old books that are still selling and selling well.
How many copies of a 2015 Paizo title do you think they sold this month? WotC is still selling thousands of SCAG copies a year. If the start banging out new books, those will inevitably lead to less sales of older titles.