There are quite a lot of predictions for the future that didn't work out -- living rooms which the housewife would be able to hose down every day, holograms, se

There are quite a lot of predictions for the future that didn't work out -- living rooms which the housewife would be able to hose down every day, holograms, self-tying shoes (yeah, I know, somebody made a pair as a gimmick). Many of them are rooted in fashions which didn't survive long enough for the technology to get there, or in cost-benefit issues. The Concorde's demise had a variety of factors that can't be summarised as, "we haven't made any improvements to transportation since then". Promising technology always, eventually, reaches a dead-end, sometimes before something better comes along, yet technology as a whole keeps progressing. The steam engine, for instance, far outperformed internal combustion engines even after ICEs became more common (https://www.conceptcarz.com/vehicle/z11210/stanley-steamer-rocket.aspx); https://www.conceptcarz.com/vehicle/z11210/stanley-steamer-r... the electric car "revolution" that's happening now also happened a century ago: https://en.wikipedia.org/wiki/Walker_Electric_Truck https://en.wikipedia.org/wiki/Walker_Electric_Truck I see interplanetary travel as inevitable because we have nowhere else left to go. There are humans on every continent now, humans under the ocean, even humans full time in space. Although there are numerous members of our species who don't now (and never have) seen any reason to leave their own backyard, our species has made it to all of these places because of the members who just can't stand to be wherever everyone else already is. For that reason alone, we will eventually become interplanetary.