AFAIK that's applying to LW 5 users.
And LW 5 users who do want to share documents with everyone (P2P Network) can do that by changing LW's options. LW 5 isn't allowing document sharing by default - it's not stopping people from sharing documents if they want to

I just did a non specific search (using 4.9.37) for lit files & found several hundred, so they are around. Rather than using the Documents search, try using All Types. Try searching for author name lit or author name .lit or book title LIT etc etc.

An 'All Types' search for Author name ebook also generated results including lit files. What you find is probably going to depend on the popularity of the author that you're looking for. Don't forget to try searching at different times of day - as people in other time zones log on & off, files available for download will change.

Something else that you can do is connect to different Ultrapeers. UPs are people who handle a lot of connections & help you to search. Because you can't search the whole network at once, changing the UPs that you're connected to will effect the search results that you see.

Click on LW's Connections tab. On the Connections page, you'll see UPs that you're connected to. Check in the Time column & see which ultrapeer has been connected for the longest time.
Right click on that host > Remove. That ultrapeer will be replaced by another. Now start a new search for your file, or search again from the download window.
If you don't see any improvement in results, remove the next ultrapeer. And so on...

See whether that helps at all

And just double check that lit or .lit isn't listed in LW's keyword filter (tools > options > filters > keyword).