I don't get the gotcha you're trying to do. Yes, the simple pattern you posted can be extended, but it has very little to do with the problem. If you had suggested [1,2,3] [4,5,6] [7,8,9] worked I would still have made my comment; I think the fact that you found a pattern that could be extended easily should have itself been a counter-indicator. Compare with something like the Fano plane[2].
I would want you to take away from this that posting the thing you came up with in "20 seconds" isn't as neutral a contribution to conversation as you thought. Things are often complicated and worth engaging with. It would have been cool if you kept going far enough to see there's a nice argument that it's actually impossible to solve it with n-sided dice for n people if n>2.
[1] https://xkcd.com/793/ [2] https://en.wikipedia.org/wiki/Combinatorial_design