No, it isn't obvious. Those of us who have flown (which is most of us) in airplanes have seen the curvature of the earth. Most people see photos from satellites and the space station. The earth doesn't look flat at all.
Besides my point was that our comprehension of time as flowing forward was far more than just a "perception".
We have all kinds of objective evidence that time moves forward which is not only obvious to the simplest of minds but scientifically provable.
That's a point I've been trying to make for a long time.
Well, to some folks who have done the math, time doesn't look flat either. That's the point I was trying to make.