The answer to this is so obvious to me that it took me a while to realize that many people are far more comfortable with 'no'.
The easiest and safest thing to do is accept what you've been 'given', to assume that you are unchangeable, and the cards you've been dealt are all that are available. When you assume this, all the responsibility for outcomes disappears, and you can relax.
When I meet people who proudly tell me that they don't read (their term) "self-help" books because they are fully set, I'm surprised. First, because all help is self help (except, perhaps, for open heart surgery and the person at the makeup counter at Bloomingdales). But even this sort of help requires that you show up for it.
Mostly, though, I'm surprised because there's just so much evidence to the contrary. Fear, once again fear, is the driving force here. If you accept the results you've gotten before, if you hold on to them tightly, then you never have to face the fear of the void, of losing what you've got, of trading in your success for your failure.
And if you want to do this to yourself, well, I guess this is your choice.
But don't do it to others. Don't do it to your kids, or your students, or your co-workers. Don't do it to the people in underprivileged neighborhoods or entire countries. Better might be difficult, better might involve overcoming unfair barriers, but better is definitely possible. And the belief that it's possible is a gift.
We owe everyone around us not just the strongest foundation we can afford to offer, but also the optimism that they can reach a little higher. To write off people because you don't think getting better is comfortable enough is sad indeed.
Better is a dream worth dreaming.