All scientific studies start from a particular premise and make certain assumptions. As such, any given study can be criticized. That’s why you need multiple independent studies and look for corroboration.
If you don’t like this study, then suggest another one that offers better results. I shall await your reply.
By the way, Excel may very well be more productive than Smalltalk. However, it’s not a general-purpose programming language. It has a very restricted application domain.