This...or try playing a barbarian with 8 strength. D&D is a game that harshly punishes ineptitude, and greatly rewards competence.
I think it all comes down to D&D origins as a wargame. Character build has little impact on roleplaying - what gets impacted is: your AC, your chances to hit, your ability to act first, your Damage output etc. There is no reward for building a suboptimal character - there is no drawback to being very strong and very intelligent. D&D got better - there is far more impact in terms of social skills depending on build, than it was the case in Advanced D&D but it is still an afterthought.
Construction of of DND and DND-like games is also important - there are combat/exploration/conversation - and those are things every character will have to engage with to a decent extend. Creating inefficient character doesn’t lead to new opportunities - it just makes him or her inefficient in the core gameplay loop.
Some do pointed out, though, that creating a well functioning character and min-maxing isn’t one and the same. The game does provide rewards, though, for being optimised, and doesn’t have much to offer for those who choose flavour. The player of course has a freedom to imagine it is not so, and do whatever they find most rewarding, but playerbase by and large will do what the game encourages them to do.
