History says otherwise. The mass immigration to the US in the 1800s was all poor people arriving with nothing but a suitcase. They moved up into the middle class and beyond en masse.
Middle class people live better than medieval kings.
I'm sure you understand how capitalism works. If you do, you should understand that not everyone can be an owner, someone has to do the actual work.
Anyone with $10 and a phone can be an owner of the means of production (by buying stock).
> It's meaningless to say
The meaning is the massive improvement in the standard of living due to free markets.
BTW, if being "poor" means being in the bottom quintile of income, there will always be "poor" people, regardless of how well they live.
Defining poverty as bottom quintile is also useless, yes. Defining poverty by comparing to the average or median income is the most useful definition. Someone earning less than half of average, for example. That tells you how well they can afford the limited resources of any society, as those track the average purchasing power.