Krasnikov tube vs Worm Holes and Alubierre Drive

[Drashner1]

So, if they all violate ANEC, why is it wormholes were chosen for OA?

Would the setting not work just as perfectly without them? Or is there a reason they are more feasible?

I wasn't present at the founding of OA, but joined not long afterward. Both wormholes and FTL capable warp bubbles existed in the setting at that time (warp bubbles were in very limited use, were tiny, and were solely the province of S5 and S6 minds). Warp bubbles were later retconned out of the setting for many years, until reintroduced in their current form as the basis for our reactionless drives (which existed in a different form prior to that point).

Both wormholes and warp bubbles in the early years of the project were based much more on popular/layman friendly scientific literature that had been written about them (mostly in the very late 80s and the 90s after Carl Sagan's book Contact led to Thorne and Morris 'inventing' a stable wormhole that didn't have a black hole sitting on top of it). They were very different from how we describe them now and with less basis in hard science. Thanks to Adam Getchell, a physics PHd, first wormholes were redesigned and warp bubbles were re-introduced.

I don't recall Krasnikov Tubes ever being discussed as a possible addition to the setting, and there seems to be much less theoretical background on them, so wormholes probably work better if we are considering the quantity of scientific papers - and presumably thought - that have been dedicated to them.

At various times in the early history of the project, there were occasional suggestions that wormholes should be removed (among other major changes), but the consensus always came back that we prefer the setting with wormholes. I don't really think you could say the setting would work 'just as perfectly' without the means to travel/communicate across large distances quickly.

Violation of the ANEC is really just an element of any kind of space-time engineering of this type (including Krasnikov Tubes, most likely), not really a problem in and of itself. That's what exotic matter/energy is for (and several current theories on WHs point to the possibility of such sufficient amounts being produced just by natural vacuum fluctuations to hold a WH open.)

Hope this helps,

Todd