Good to know that Bill Gates shares this viewpoint. It's not that space travel is wrong or doesn't have great potential. It's just that, in my view (and I guess it's also BG's judging from his short quote only), it cannot not alone bring humanity into the bright future. Look at how we are (mis)treating the environment. Look at all the greed, corruption and anger around us. Anyone seriously thinks going to new worlds will change these human tendencies? Of course not.
I see only one truly worthy alternative - education, with strong emphasis on sustainability and care about the environment, as well as some sort of moral principles that would help prevent spending trillions on new ways to kill each other (aka defence) in future generations.
I see only one truly worthy alternative - education, with strong emphasis on sustainability and care about the environment, as well as some sort of moral principles that would help prevent spending trillions on new ways to kill each other (aka defence) in future generations.