To me, it seems that you're not fully responding to the bits that I've bolded:
The worry about "do I want to find out if I can be as lucky as Joe?" seems appropriate to an early D&D luck-based dungeon. Lewis Pulsipher wrote about this in White Dwarf 45-odd years ago.
But I don't really feel its force in the context of the games/designs that
@Neonchameleon is referring to. In those games, to play the game
is to take risks. (Eg in Burning Wheel, the rule for
a roll is required is
that something is at stake, as per the priorities that the player has established for their PC. So if it matters, then there *is a risk.)
And pushing things, as Neonchameleon said,
doesn't "put you on a road to ridiculous effortless power". It puts the PC on a "highway to hell" - that's what the play of the game consists in. And learning - that is, advancement of PC attributes - arises from taking risk, from failing, from getting traumatised, depending on the game. (Compare eg Burning Wheel to Dungeon World.)
There's no opportunity, in these games, to "stick with the middle". That's like turning up to play bridge but not wanting to take the risk of being dealt a hand: it's not a way to play the game.