MarciK - you may own one edition of a book that is not on many Bookshelves but when added together with all editions then it reaches our indexing threshold. Or it may have been member indexed, when the popularity does not matter.
I took a look at your Bookshelf and can answer these specific examples:
Best Ever Indian Cookbook - your edition is on on 2 Bookshelves (BS) but all editions together total 124
Time Honored Norwegian Recipes - your edition is on 2 BS, the total is 10 and it was indexed by a member indexer
Jamie Oliver's Christmas Cookbook - your edition is on 7 BS but the total for all editions is 573
The Little Bahamian Cookbook - on 10 BS and indexed by a member indexer
The Lady & Sons Savannah Country Cookbook - your edition is on 9 BS but all editions together are 329 BS
Williams-Sonoma Essentials of Roasting - your edition is on 10 BS but all editions together total 190 BS
As for books you own on over 100 BS that are not yet indexed, we do try to chip away at indexing older books while also keeping on top of the many great new cookbooks being published every week. Some of the older books that are unindexed are huge (over 1,000 recipes) and more than 20 years old. We do not have unlimited resources so we have to prioritize our indexing to the books we feel will give the most benefit to the most members. Every member would like more of their Bookshelf to be indexed but you all own different books.
You have more than 25,000 indexed recipes on your Bookshelf from the cookbooks and magazines that are indexed. So I hope you will consider the great benefit of that more than the disappointment over unindexed books you own. It is quite likely that you own books that will never be indexed (unless a member volunteers to index it) but your recipe count will increase over time as more of your books are indexed, or you buy new books that we have indexed.