That is interesting and it's something I've been considering. Most people are sure this is motivated by money/ransom, and maybe it is, and probably still the most likely motive, but I'll say it doesn't fit the typical ransom case.
No clear line of communication. No proof of life. Why haven't they provided this by now? Why haven't they given some type of definitive proof they are the actual kidnappers? I mean, we're almost two weeks into this and LE still doesn't know with 100% certainty the ransom notes are from the actual kidnappers.
The fact that this case doesn't exhibit the usual steps that ransom cases take has left the door open for me that there is some other motive here. And one of those possibilities I wondered about was did Savannah Guthrie have some obsessed stalker fan... he went to that house expecting to kidnap Savannah and not her mother? He was surprised about who was inside, and then kidnapped her as some sort of demented consolation prize? This doesn't seem super likely either, because I figure if someone was after Savannah and didn't find her there, they'd just flee. But nothing about this case fits the typical makings of what you usually see in these types of cases.