I couldn’t find an average thickness of books, so I quickly measured the 2nd from top shelf of my closest bookcase. (The top seemed unfair as it has a collection of “the world’s famous orations” which seem abnormally thin ). Shelf in question: https://ibb.co/CznTZ5m

(Googling I just seemed to get spine thickness and format sizes but not an average of actual printed thickness )

It has 21 books in 28 inches.

1.34 inches per book.

I get 279 linear feet for 2,500 books.

Checking Amazon, Walmart, the book cases they sell seem to be 5-6 tier with 24 inch width. (Though checking my non built in ones, all of the ones I own are around 4 feet).

Using the Amazon average, you’d need 24 book cases to fit all of them… which does seem like a lot. Wonderful but a lot.

I do have a kindle, and I love it. But something about physical books is great.

I have 5 built in book cases of various sizes, and 6, four feet Wide book cases that are 5 or 6 tiers… and yet I still have bins and bins of books in my attic.

Initially I had thought “that’s manageable” but upon some self reflection you make an excellent point.