The author is projecting his own perspective onto the Zaklos' story. They didn't choose between spiritual and physical. They arrived at a place that relative to their previous life to that point was both a material and spiritual עולב מדכדך and they experienced a transformation in both of those realms. It's a false dichotomy the author creates. Yes, there is a challenge in abundance as well, but that is the challenge of our generation, to learn how to synthesize the two with אורות דתוהו בכלים דתיקון
You are missing the writer's point. The writer isn't inferring that the choice we have to make is the same as the choice the Zaklos' made. The Zaklos' choice wasn't between גשמיות and רוחניות. It was about going on shlichus, and they gave up on "anywhere but Russia" because they realized that was the right thing to do, and made a choice, and as an outcome of that choice, they were successful.
The point the writer is making is, unlike your statement that "there is a challenge in abundance as well, but that is the challenge of our generation, to learn how to
synthesize the two with אורות דתוהו בכלים דתיקון", the fact remains that we say every day "והאר עינינו בתורתך, ודבק לבנו במצותיך, ויחד לבבנו לאהבה וליראה את שמך", with countless references in Chassidus about how our רצונות ותאוות should be in אלקות, and that having our רצונות focused on תאוות והנאות עוה"ז are diametrically opposed to having them in אלקות.
While we are in דור השביעי, and נסתיימה עבודה הבירורים, etc. etc. none of that negates the fact that wants and desires of worldly luxuries are (especially when talking about setting an example for children) an educational contradiction to the aspiration to have the wants and desires focused on תורה, קדושה and אלקות.