[nivertech]

1. back in the day high-level programming lanaguages were also a business model. In order to sell their computers the HW vendors would provide a FORTRAN compiler for free.

2. Declarative programming can work for narrowed problem domains using DSLs/middleware, but not in the generic case. If you don't want to be locked, either chose a standardized DSL (e.g. BPMN), or implement compiler/interpreter/runtime/middleware by yourself.

3. SQL originary targeted end users (Analysts), but today it mostly target developers and DBAs. Today end users would mostly use BI tools or dashboards, not SQL directly. So I wouldn't use it as an example of Declarative Programming.