Fall TV: What is it with time travel this year?

To wit:

• The Flash. Episode one and we're on our third reality of the season.
• Legends Of Tomorrow. Time travel is the whole schitck, although it will probably take some kind of left turn this year.
• Timeless. Personally if I was in this boat I'd ask Homeland Security to write up a dossier of my complete life so that it would be the first thing I read when I got back. Nothing like getting blindsided by (A) a missing sister and (B) a fiance.
• Travellers. Hasn't started yet, but I understand it too is a time travel gig.

Odds are at least one of the latter two won't make it to Christmas.