SF Cliches

If mankind really does have any kind of interstellar or galactic future, will that future be anything like what many sf writers have imagined? It is not just that many individual writers just happened to imagine the same kinds of things. Rather, a set of convenient assumptions and cliches emerged within the literary ghetto of genre sf whereas Wells and others had written imaginative fiction before Gernsback created the ghetto.

The cliches are:

interstellar travel that is not only faster than light but also easy and cheap;

governments and other organizations able to operate on an interstellar scale;

many inhabitable but uninhabited extra-solar planets, easily colonized;

easily comprehensible humanoid aliens engaging in the kinds of economic, political etc interactions that are familiar from human history.

I ask this because, in Poul Anderson's A Stone In Heaven, Dominic Flandry and Miriam Abrams drink and talk in a luxuriously appointed bar in a spaceship that flies itself between stars at many times light speed. Is that remotely plausible - or does it sound just a little too easy? I hope that, by the end of this century, mankind will have resolved some pressing problems on Earth and will have moved out into the Solar System but I really do not expect spaceships like Flandry's, do you?

It is the prerogative, indeed the responsibility, of sf writers to question and challenge every assumption and cliche. Fortunately for us, Poul Anderson:

wrote very high quality genre sf;

combined it with speculative fiction;

followed his Technic History with The Boat Of A Million Years, the Harvest of Stars Tetralogy and Genesis, all based on completely different futuristic premises.