I remember a long time ago, back in the earliest days of 5E, I ran a short campaign where everyone started with 10s in all of their stats except for two: one stat of their choice could be 12, and another had to be 8. Then they could all add on their racial bonuses. The idea was that their characters would start out as ordinary folks who rise to greatness, through struggle and adversity.
Everyone hated it. The players hated not getting to start with a +4 (or higher) bonus, and the longer they had to wait to get a 20 in their favorite stat (Dexterity. It's always Dexterity) the more hateful they became. And I hated hearing about it constantly, in every gaming email and at every gaming session. It was a mess, and I don't recommend it.
For better or worse, players don't just expect to start the game with high stats--they demand it. So I oblige them. After all, I can always adjust the dungeon's math to compensate for the characters, no matter how optimized they are.