We all win when folks decide to leave it accessible, but I'm not going to hold "encrypting a file format so that people can't easily reverse engineer it" against folks who are trying to sell software.
https://www.sqlite.org/see/doc/release/www/index.wiki
There are third party encryption approaches for SQLite. One of the most popular is SQLCipher:
https://github.com/sqlcipher/sqlcipher/
Those two don't have compatible file formats. eg no interoperability
Not sure if any others do, but yeah it would be handy if there are.
I think I'd mostly disagree. Selling an application is one thing, but the data itself is usually customers' and holding their data hostage is not a proper thing to do.
Listen to what you're saying: the data isn't locked, you just need the... application, to... unlock it.
That's beyond tenuous, it's invalid.
That argument that a proprietary file format "locks" data ignores the fact that it's the pair {application, file} that determines whether your data is locked away or not. For instance: Microsoft Word data? not locked. You can trivially export it in quite a lot of ways. Can you easily get it from a traditional .doc file? Hell no, but that doesn't mean the data itself is inaccessible. Instead of using sqlite, or xslt, or PERL, or whatever, you use word.