I don't think you actually used those books :-/

No one linearly writes code, from the start of the file to the end; they edit it. They move blocks around if they missed a page, they navigate around putting in missing if statements and removing incorrectly-added loops. Those programs were very much not one-and-done, they were heavily modified by the kids.

Your proposal of "Tell them to configure their editor for Python" and "add in unicode symbols to represent whitespace" is the exact opposite of what those books were about.

The books were about removing superfluous barriers, not adding them! Using Python would result in a whole lot of incidental complexity for literally no gain.

Education has already chosen Python as the preferred language for this sort of thing. It has some unfortunate bits, but it's certainly a more ergonomic language than BASIC. Counting tabs is less arduous than messing with line numbers and GOSUB.