Because the vast majority of Access users have it installed locally on their PC already as part of Office, and have never heard of SQLite. And even if SQLite was installed, you'd also need a different program altogether to actually view or input any data. Access includes the engine, the GUI, the query tools, the form builder in a single program.

Access is both a database engine and an UI and forms builder. You can easily design a database and make queries in the UI, and you can create custom forms to the extent that is doesn't look like a database anymore but just a custom desktop application. You can do that without any programming.

This is like saying why would anyone use a Toyota RAV4 when they can get a 400+ hp LS3 crate engine from Chevy. Is it because of the quality of the dashboard plastics?

I really like this analogy. The question you were responding to has been asked - in one form or another - so many times on this thread that its clear that those developing software and business tools are completely out of touch with users and power users of those tools.

I mean, the crate engine is cheaper, lighter, far more powerful, and you can buy one labeled "turnkey"!

You can make a nice UI very fast. Forms, fields, buttons. It's nothing like SQLLite which is just an SQL engine.

This is like saying "why would anyone use dropbox when you can just run rsync on your Arch linux box."

To me the main feature of both Access and SQLite has always been the fact they're single files. Very easy to manage.

Exactly. And a nice programming language. The engine doesn’t really matter. You could create something like Access on top of SQLite.