Both of my grandpas (who have passed away long ago), would beg to differ. People, especially when taking photos wasn't basically free, don't take photos of ordinary things. If you see 1 rose among 500 tulips, that will catch your eye. And vice versa.

Poor people were not hidden away, it's just their lives weren't that beautiful to be shown and paraded around.

Most of the people in the photos seem be ordinary, working class people. Even buddhist monks, who swore to live in poverty, celibacy and to avoid food that was too flavorful.

It isn't like we don't have records of ordinary people, even the homeless, or criminals. It's more like people like you claim the existence of a whole another kind of "poor people", who were supposedly the absolute majority, who suffered somewhere, completely ignored by everybody, and worked long hours every day on... being poor? It just doesn't seem to add up.