Any Alternatives to Filemaker WebDirect?

I would like to create a custom database application and place it on the web as a public-facing web app.

Obviously I could build something like an SQL database with a PHP front end. Filemaker is so much easier; but the pricing of Web Direct is outrageous even for a small group ($2700 a year for 5 concurrent connections) and impossibly priced for a public facing website. It is even price absurdly if I am using my own computer as the server.

Any idea why they price it this way?

Are there any alternatives that are realistically priced to use on a public facing website?

SQLite? PostgreSQL? MySQL?

Airtable? I’ve been pleased with it but it depends on what you’re trying to do.

Airtable is certainly popular - but honestly I am not impressed with the front end - all their databases seem to wind up looking pretty similar and not that much different than a spreadsheet.

SQL and its relatives certainly work as databases but require lots of work to build a front end to them.