That is still very optimistic. If one of us saw 0.00001% that is still 40,000 systems, or 5 1/2 times the total systems in Eve Online counting regular and wormhole space.
400 billion systems is a hard thing to imagine (DB and the videos say 400 billion, not 4 or 100). Really it is so large it borders on ridiculous. If ED sold 500,000 units, that would be a personal domain of 800,000 systems per person. If you played 12 hours a day, every day, and spent 10 minutes in each system, it would take you over 30 years to visit your personal domain, and that is for each of those half million people. If everyone in the world played ED, they could each have 57 systems to themselves.
If we were to calculate the galaxy as a cylinder 500 systems deep (that may actually be too deep, not sure if there are 500 systems in a vertical slice) then it would have a diameter of 31900 systems. If it took averaging a minute to jump from one system to another, that would take 532 hours to fly from one side to the other, or 44 days of flying 12 solid hours a day. If the depth of the galaxy were more like 400 deep, then make that 50 days to fly across.
To quote HHG2tG: "Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is."