A twisted neck is comfortable because we have all got in the habit of playing with the instrument parallel or nearly so to the floor. A straight neck is perfectly comfortable if the bass is played at around 45 degree angle or so. An extreme of this was Bill Wyman, who went nearly vertical, but many players from 60s bands used to play at a good angle. This has almost disappeared now. I find it very comfy at an angle, but then I play double bass too, so I'm quite accustomed to holding my left arm up and having an imaginary tennisball held between my left elbow and my left side.
The older I get, the better I was....