Yes they were, extremely poor.
Child mortality rates and mortality rates in childbirth have been c. 20% for most of human history, up until c. 1940.
Almost all human beings for almost all recent history have been agricultural works (over 90% in 1800) which is a severe and precarious state.
If you wish to go before settlements into nomadic hunters and gatherers note that this cannot produce "mathematical research, healthcare, etc." -- ie., the desirable things stated.
At this point you're just pining to be a dog. You may prefer a shorter, more brutal, more violent life... but I think, rather, you just need a fantasy of a utopian "before time" to justify you enmity towards the status quo.
> how some can claim Capitalism is the important factor here.
Err... when do you think they started their massive reductions in poverty?
When they stopped blaming various other people an liberalized their markets (in china "The Capitalists" and in India "The British Empire"). Within a few years of introducing captialist reforms these societies dramatically reduced poverty.