You can absolutely add new fields to database tables on the system without updating every program - if you architect the software properly. Use embedded sql, explicitly select field names (ie don't do "SELECT *"), and put default values on new fields. I haven't written a new RPG program using the old file-specs in years - all new code has been embedded sql.

Not willing to give up SELECT *? Fine - create views on top of the real database tables to do your SELECT * from. Then you can still add new fields to the database tables without changing everything else.

Edited to add - if you want to add new fields to a table and not change all your old programs to use SQL, create a new table, transfer your data, and then create a view with the old table name using the same fields. You just have to test a little to make sure your view has the same record format id as the old table. Honestly it's pretty easy once you get the first one done and see how to do it.