The time/cost savings from not having a physical book is well offset by the amount of time needed to a) support patrons use of ebooks via apps and backends which deliver the books and b) administrative time purchasing and dealing with the publishers.

Income is lost because ebooks are never overdue and so fine income is significantly reduced over physical books.

Floor space is not reduced (we have plenty of books that need to be shelved) and reshelving costs are the lowest of any costs in the organization due to the fact that a lot of reshelving is done by volunteers.