One problem, other comments hint on the same thing, is that poverty is not an absolute, it's relative.
We would consider ourselves poor if we lived as a family of five in a tiny early 20th New York immigrant's appartment, even though we'd be much better off than a feudal peasant living in a straw hut with no electricity and a distant water well (the "working class" of its day), which in turn would be must better off than some early aggrarian iron age person (even an upper class one). So, in some sense, poverty must be estimated with regard to access to the standards and niceties of the era (and is therefore connected to inequality).
In another sense, poverty is also qualitative and cultural, and working as a factory cog in a sweatshop for $3 dollars might be worse than living as part of your traditional tribe (and their lifestyle) for $0 dollars. And yet, we herald people whose native lands have been plundered (or whose local e.g. farm income has been destroyed by cheaper imports) and are forced against their will and to the detriment of their lifestyle, to seek work in the cities as a triumph over poverty.
What can be measured well, is whether we have greatly reduced hunger and childbirth deaths and such metrics.
But poverty is too flexible and abstract a term to say we have "ended" it. Else we'd have already "ended poverty" when we moved from the caves to early cities and huts too - as everybody had raised their income levels and owned goods and such. And yet, poverty just reappeared in a different relative level.