Rutherford was always making claims like that.
Many of his claims dealt with invisible happenings in heaven that were impossible to disprove.
Nothing visible ever happened in accordance with his earthly predictions, but he just distracted JWs by making more dogmatic pronouncements.
Many left, but a lot of people drank the Kool-Aid and became numb to his string of prophetic failures.
Some even saw his failures as successes through "eyes of understanding."
If you show such statements to most JWs today, it doesn't faze them at all: They either denounce it as apostate literature or just pass it off as "old light."
Amazing... and truly sad...