The way I understand it, long term thinking is neither about the future nor about predicting it or planning something significant for it; it is rather a thought model which tries to extend beyond the timeframes humans might feel at home with cognitively. An off-the-cuff, superficial yet interesting example is the lack of a common word in English language to express units of time longer than 1000.
This style of thinking sometimes has its benefits, like gathering together a community to build a mechanical clock, create a manual for restarting a civilization[1], or write a non-fiction book about "earth without people"[2].
It's just an interesting intellectual, cultural endeavor.
[1]: http://blog.longnow.org/category/manual-for-civilization/