A range of 14-20 reasonably successful pulls sounds about right to me.
Ah, 14 is the highest you can reasonably get, with pretty much the best strategy. 20 is what you can get if you succeed with every 5d6 roll, but if you roll 5d6 more than once then you're more likely dead than alive. Any mix of 7, 6, and 5d6 is worse than just 7d6—you get the possibility of some more rolls/turns in the future, but you're much less likely to get there.
It's very unforgiving—deviate from the strategy and you die quick or cut your game short by wasting dice. The problem then is either people go with the best strategy for part or all the game (so they have less/no choice) or they gamble and fail quick (so they don't play for long enough to have many choices). Most people aren't gonna figure out a strategy, so they'll go with option 2.
Interesting! Personally, I would say that if I tip over a Jenga tower, it feels a lot more like my fault than if the dice I rolled ended up being low. That's not to dismiss your point of view: just saying that I don't share it.
Yeah, 'more' was the wrong word—but it still has a single clear point of responsibility (making a single bad gamble) where jenga's drawn-out.