Delphi and Free Pascal are a bit too far removed from Wirth's idea of simple languages which is probably why he didn't mention them. Delphi 1 (let alone the modern variants) added more stuff to Turbo Pascal than the entirety of Wirth's Pascal and it is more of a new language that has his Pascal as roots - after all programming languages affect how you think about the solutions of the problems you are trying to solve and the way you'd write a Delphi/Free Pascal program would be very different than the way you'd write a Wirth Pascal program.
Notice that he sees Oberon as the successor to Pascal and Oberon is an even simpler language than Pascal was.
My respect for Wirth only grows over time. He has this philosophy that strikes me as Bauhaus, a focus on futurism w/o complexity, clean lines and modern technology.
Notice that he sees Oberon as the successor to Pascal and Oberon is an even simpler language than Pascal was.