It seems like it's always the same handful of texts. Ancient readers liked what they liked and weren't out for variety it seems.
At the same time, Juvenal has a whole satire about how everyone is trying their hand at writing books and mentions in another how booksellers are always getting new volumes.
I spend way too much time pining for the chance to read the other parts of the Trojan Cycle, even though the ancient said they were much lower quality. Like your favorite show getting canceled.
Also, Juvenal was a poet. He most likely knew other poets, or aspiring poets, or at least people who liked writing. Your average, generally functionally illiterate, individual at the time is not trying their hand at writing books.
This is present even today, I saw a burial in Eastern Europe where the parents put a game of chess and toys in the coffin. While it will do no good to the deceased my theory is that it is a way for the living to deal with the loss.
The more who believed that, the less power their religion had at holding the empire together until it transcended into becoming a vassal and later out of existing. Religion was the foundation of the empire, but judging from the many artifacts we have, at least some did take it very seriously.
Spoiler: they do that so that future grave robbers and archaeologists will know all about the dead person's lifestyle. Surely that kind of everlasting glory has to be worth something to the deceased, one would think?
https://notebookofghosts.com/2016/11/21/a-list-of-weird-thin...
(See "Saint James Infirmary Blues").
"Book" has been used to translate the Latin word "liber", which is the word used by the Ancient Romans for the parts of a bigger document, each of which would have been written on a different scroll.
Latin "liber" was used to translate the Greek words "biblion" or "byblos", which are thus the oldest source of the word "book". "Byblos" originally meant papyrus in Greek, but later it was also used for the parts of a big document. A later form of this word, which was more specialized with the meaning of "material for writing" or "book", is "biblion" (a diminutive), having the plural "ta biblia" = "the books", which is the source of English "bible".