Smalltalk/V on DOS (1980s) had extra runtime royalties payments which was too expensive for deployment. So other 4GL languages like dBASE/Clipper/Foxpro or even C Language without those costs were more attractive.
The later Smalltalk/V for Windows did eventually remove the royalties but the base dev package didn't include ODBC database connectivity for free. (I think you had to pay extra for the Digitalk PARTS Workbench with db drivers?) In contrast, Microsoft Visual Basic had free ODBC drivers to connect to Oracle, Sybase, etc.
Of the dozens of companies I interacted with for LOB (line-of-business) applications, Smalltalk was never even a consideration. In the early 1990s, there was modest hype and popularity with Powersoft PowerBuilder which was more of a competitor to MS Visual Basic for internal corporate apps than Smalltalk or Java.