Constructing machinery has huge environmental costs as well. The CO2 emitted in the construction of a car rivals that emitted by driving it afterwards, for example.
Getting into orbit requires a huge amount of energy. That's just physics, and there's no way around it. Spending lots of money on extremely complicated and efficient machinery to use less fuel getting to orbit does not mean you're more environmentally friendly.
Also, numbers matter. The environmental costs of space travel are completely insignificant, while cars are choking the planet, simply because there are billions of them. A tiny efficiency improvement applied to billions of cars will dwarf a gigantic efficiency improvement applied to a few rocket launches per year.
Good point about billions of cars having more impact than a few fuel-hoggy rocket launches.
I just hope that space-tourism doesn't catch on, because while you're correct that overproducing rockets to make them slightly more efficient does not make you more environmentally friendly, burning 25,000 gallons for a couple of recreational hours off the planet just because you have way too much money does make you an environmental monster.
Getting into orbit requires a huge amount of energy. That's just physics, and there's no way around it. Spending lots of money on extremely complicated and efficient machinery to use less fuel getting to orbit does not mean you're more environmentally friendly.
Also, numbers matter. The environmental costs of space travel are completely insignificant, while cars are choking the planet, simply because there are billions of them. A tiny efficiency improvement applied to billions of cars will dwarf a gigantic efficiency improvement applied to a few rocket launches per year.