I agree that if it is advertised it should work and work well. It is not that an ereader has to process all the books you have on the device every time you open a collection and it makes me a bit uneasy wondering just why they do that. A book is a file and even a rudimentary file system should be able to process hundreds of books in a collection o if they have some obscure reason for doing it. The fact that some much older readers do it with 5000 seems evidence enough that it can be done.
The reason I want a lot of books on my reader is that I read a lot. I have also been reading for a long while. Consequently I have at least 800 authors I am wanting to read that I know of. Many of these authors have written more than 50 books.
Rex Stout, for instance has written around 60, and I have read more than 40 of these. I am trying to save some for my deathbed
but if I wake up at 3AM and I want to read a Rex Stout book that I possess, I don't want to stagger out of bed and turn on my computer and side load it, deal with the little tiny browser screen and download it from the library or the cloud. A well organised paper book shelf would be easier.
And I might read a typical Nero Wolf novel in an hour so would like to have another handy just in case.
Then I want to expand my horizons by reading books by authors I have not read before or on subjects I am interested in.
I try to read at least one in 5 books by an unfamiliar author. Generally I get them from the library and have a library collection. More incentive to read them if they have to be returned.
I am interested in a fair range of nonfiction. But enjoying fiction a tad more, I would seldom read books on different cultures, cognitive diseases and conditions, retirement planning, health, politics etc. if I had to make an additional effort to put them on the reader. I have them in a collection called other topics.
A lot of other reasons I have lots of books on my reader, many the same as having had lots of books on my physical bookshelves. I have had thousands of books on my bookshelves and in boxes in the basement. Sometimes I read 2-3 books a week and sometimes 2-3 a day. So I got in the habit of stockpiling books
Couldn't just wander off to the library or Chapters at 3AM.
I guess it is each to their own. If you know for certain the next 6 books you want to read, why have more. Finish one or two and put on one or two.
If you want to read 10,000 book, even if impossible, and are a mood driven reader like me, you would be up and down all the time second guessing your next mood. On my Sony I have a lot of books because it is easy to browse for something different. On my Kobo's I have a lot less, because browsing is painful, so I only have tried and true authors on them.