I see claims like this fairly regularly when works touch on pre-roman Germanic cultures but never really see a source. These notions also seem like something which would significantly impact the functioning of society yet such impact is never elaborated upon. Are these just misconceptions that ended up on popular consciousness or am I missing something?
The lack of a concept of future might be a misunderstanding of the fact that Germanic languages lack a distinct future tense compared to other Indo-European languages. Technically they have a past and non-past tense, and form the future periphrastically. This is why in English we say: "I will do that tomorrow".