So true 
!
Multipage TIFFs used to be rather more common round then; I remember my fax software produced them. Opening them in anything other than the fax software showed an illegible image compressed to half its height. And only one page, unless the software happened to support multipage. Fun and games in the good old times, hey?
Offtopic: Does anyone know a Command Line Tool that creates PDF X3 from a tiff?
I doubt that such a thing exists. PDF/X is a special format for professional printing, and the people in that business are not known for their fondness for the command line. Obviously, Acrobat, InDesign and the like can produce the format. Since they’re scriptable… Only joking
What are you planning to do, where do the TIFFs come from?
My brother produces the tiff and his clients expect PDF X3. I‘ve never heard of it before and forgot why he needs to do it via Command Line … Thanks!