You and I seem to have a similar background. I was a huge fan of Fortran. I was also a huge fan of OS/2. I bought OS/2 Warp for my personal use.

It's a great pity OS/2 didn't survive.

You won't find Smalltalk used in all application domains. It is, in fact, favoured in some industries much more than others. FYI, Telecom Argentina is a major Smalltalk user.

Like I said, not many enterprises know about Smalltalk. It's a well-kept secret. Businesses in the know use Smalltalk as a competitive secret weapon.

FYI, my productivity claim comes from a 2017 study by Capers Jones, the world's leading expert on software metrics. This comprehensive research studied thousands of software projects and millions of lines of code over several decades. Not only that, it covered the Total Life Cycle cost, including requirements, design, maintenance, etc. No other study has ever attempted this on such a scale.