Well said. I'd also add not everything is unachievable just because it hasn't been done yet. A lot of people won't even update their priors once something is done (belief perseverance). I've lost count of the number of older people that tell me electric cars won't work whilst there is a perfectly functional one sat on my driveway.
But not everything is achievable just because we want to achieve it. Physics/chemistry also have a say in it.