So if I recall correctly, I remember an interview awhile back where one of the developers was talking about how the game is essentially designed with characters having a 14 in their primary stat, due largely because people weren't garanteed to have rolled well or have been the best optimizers (yes this does cause issues for actually optimized parties).
That said, foe our groups, we tend to use point buy with 30 points, mostly give a slight bit more oomph to the average points.
More relevant to the topic, I feel it important to point out that while rolling techically has more possibilities, many of them are either unplayable or absurdly broken and should not be considered valid options. As fun as it is to envision all 18s, I sincerely doubt any DM would allow that character to ever see play at a table, and frankly anything that doesn't have at least one 12 (arguably 14) shouldn't even be viewed as a valid option to roll.
I heavily reccomend for those seeking to roll characters at a table, rather than just 3d6 or 4d6 drop one, you just do "2d6 (or 3d6) + 6" for scores. Or if you want a game where a 6 is a valid roll, use +4 instead.