DND_Reborn
The High Aldwin
Surely 8 Int is also just...the low end of average. Not even enough difference to be noticeable under any circumstances other than detailed testing of intellectual capability. 8 Int is still someone who graduates high school without any particular trouble.
I agree an INT 8 could finish high school but IMO it wouldn't be the low end of average. I think they might have a bit more struggle along the way than an INT 10 or 12.
If you follow my belief that each +/- 1 represents a standard deviation, than an I.Q. 71-85 would have an INT 8-9. This was supposed to be the I.Q. of Forrest Gump who had a I.Q. 75 IIRC. So, fully capable of doing what nearly everyone else can do, even if there might be some times of struggle or taking more time, etc.
All that being said, I think a bigger part is the fact that INT represents an ability. A lower INT could simply be someone who is actually smart, but forgetful. Or with a great memory, but not as clever as most. Or perhaps some other aspect of their INT is severely lacking while others are a bit better than normal? That is the problem since each ability score represents often 3 or more aspects... you just don't know which is affected and such. Of course, this also means you can interpret your dump stats if you have one in whatever manner you wish, but mechanically it is all the same.