You can totally shave off the 8 with point buy. Yes, it will cost you on the upper end of your ability scores.
Remember, 10 is "average" and 8 is just slightly below average. A character with 8 intelligence would still be able to read, write and communicate, at least in a modern society where literacy is taught to everyone. I think most of us would be hard pressed to say there is no area in which we are below average.
But hey, if characters with limitations in their abilities isn't your thing, and you have a group that feels similarly, there's nothing wrong with bumping up the power level on the point buy.
I'm not running the numbers rigorously, but there's a 17.5% chance of rolling 9 or less on a 4d6 drop 1. So, with 6 ability scores, that makes the odds of getting at least one low score fairly high.
I'm an old school grognard person and we rolled using Gary Gaygax suggestions then and now.
1e DMG pg 11 "As AD&D is an ongoing game of fantasy adventuring, it is important to allow participants to generate a viable character of the race and profession which he or she desires. While it is possible to generate some fairly playable characters by rolling 3d6, there is often an extended period of attempts at finding a suitable one due to quirks of the dice. Furthermore, these rather marginal characters tend to have short life expectancy - which tends to discourage new players, as does having to make do with some character of a race and/or class which he or she really can't or won't identify with. Character generation, then, is a serious matter, and it is recommended that the following systems be used."
1e PHB pg 9 "Furthermore, it is usually essential to the character's survival to be exceptional (with a rating of 15 or above) in no fewer than two ability characteristics."
What it really comes down to is what you think is good enough for a 'heroic adventurer', standard array and 27-point buy doesn't work for me. 35+ point buy with an 18 cap and also a max starting stat of 18 would work. 5e is very flexible so higher starting stats can be readily adjusted for.