Why is no one using local/offline search engines?

I've got lots of books/pdfs and plaintext notes. With so much information, I often need some means of searching over it.

However, literally the only app I know of on Linux is Recoll [0]. On Android, the closest app I've found is DocSearch+ [1], which isn't open source.

Do people not see a need/usecase for it? Is everyone relying on cloud apps? Is there any interesting work in that area?

Why is it not part of everyone's desktop environments/shells? Our computers and phones are powerful as ever, we can totally afford to have a proper full text indexer (with stemming/query language/etc.), running in the background.

[0] https://www.lesbonscomptes.com/recoll

[1] https://play.google.com/store/apps/details?id=com.docsearch.pro