If you're arguing that the market dynamics are driven by the existence of a cap on consumption, in contrast to other goods, your argument must fail if the cap isn't actually restricting anyone.

There is an infinitely high cap on the consumption of every good. That can't distinguish anything from anything else.

So...

> Would a figure of 60 books per year change the argument? 100? 200?

Yes, that's the difference between the argument being theoretically able to work on its own terms, or not.

>There is an infinitely high cap on the consumption of every good

Huh. No, no there is not. This is why a few rich people don't consume 100x as much toilet paper as you do. The cap isn't how much of the good we can make, the cap is human time and attention, of which time is fixed and attention is a highly competitive market. Simply put people are not buying infinite books and immediately throwing them in infinite fires.

Let me try adjusting for a very low level of reading comprehension:

1. All goods have capped consumption. There are no goods without this feature.

2. The cap might be very high.

3. If you want to argue that one good differs from another good by virtue of capped consumption...

3(a). It is not enough to show that a cap exists;

3(b). Instead, you must show that the cap is actually achieved.

4. The reason for this is that the cap exists for all goods.

5. Books do not come anywhere close to reaching their consumption cap. The consumption of books is just as unbounded as the consumption of immortality pills.