I think the author is so enamored with Smalltalk that they no longer see how quirky and non intuitive the Smalltalk syntax is. Case in point:

    ourList := { 1. 2. 3 }.
    ourList collect: [:in | in + 1 ].

Here it is in Kotlin:

    val list = listOf(1, 2, 3)
    list.map { it + 1 }

No spurious colon, dots sprinkled a bit everywhere, mysterious ":in" or pipe bar, square brackets. Just a very naked syntax.

Next:

    ourList select: [ :num | (num \\ 2) = 0  ] thenCollect: [:n | n + 2]

Kotlin:

    list.filter { it % 2 == 0}.map { it + 2 }

The next example is an ever better illustration of why Smalltalk feels so antiquated and wasteful, and is not respecting the developer's time:

    ourList chain
      select:  [ :num | (num \\ 2) = 0  ];
      collect: [:n | n + 2];
      collect: [:m | m + 2].

Why do I have to find names for all these closure parameters? And why use a different name every time (num, n, m).

Again, Kotlin shows how to do it right:

    list.filter { it % 2 == 0}.map { it + 2 }.map { it + 3 }