i wonder whether it is an accident that "spaceships" are called after ships

ship (plural ships)

1. (nautical) A water-borne vessel generally larger than a boat.

2. (chiefly in combination) A vessel which travels through any medium other than across land, such as an airship or spaceship.

Spaceship is a portmantau of space and ship, so nope :)

I don't think tablets existed in the 20th

Ships, including ocean-going ships, were a thing long before 15th century. Europeans have travelled to North America in the 10th century. What happened around the 15th century was the creation of empires willing and able to colonize (plunder, steal, enslave) on a continental scale. The idea that the amerikas were somehow "the new world" rather than land stolen by massacring natives is imperialist propaganda. I think this is the reason why a lot of people fell for "colonize mars" bullshit - they subconsciously think that the land now occupied by the US was a barren wasteland which couldn't support human life until brave europeans came and covered it in McMansions and fast food chains. From that mindset it makes sense that we can do the same again, but with mars.

This isn't a meme and the comparison is wrong.