were people 700 years ago way smarter than today?

[major_setback]

Dear, dear, oh dear.

Re: 'Survival of the fittest'
It is one of the most misunderstood and wrongly used quotes in the world and it wasn't even coined by the man it is mostly attributed to.

From Wiki:
'Darwin first used Spencer's new phrase "survival of the fittest" as a synonym for natural selection in the fifth edition of On the Origin of Species, published in 1869. Darwin meant it as a metaphor for "better adapted for immediate, local environment", not the common inference of "in the best physical shape"'



Darmwin meant that those individuals (animal/human) best adapted to their environment would be those most likely to reach breeding age and therefore be able to pass on their genes to the next generation.

fittest = best fitted (not the most physically fit).

Being the strongest and fittest individual will not help you if you are not adapted to survive in a changed environment.

I think humans have adapted well and will continue to do so, so I don't at all agree that the phrase has no meaning today. And it even applies at an individual level. If you can't adapt you won't make it (it applies not only to physical adaptation but to behaviour/strategy too).