It's not really fair to use $1.90 per day as a standard to judge someone is poor because each country has a different currency, minimum income and living cost. $1.90 per day in first world country is definitely a poor, but for third world country, such amount might be normal for them because they can still live with $1.90 per day.
I think that it's enough to be considered because if we complicate things just to suit it with other countries' living cost per day, you'll either get a number that close or it's going to be even lower just to do an average. I don't agree with an assessment that someone's "living" at that amount, they could probably buy a meal for only once with that money in my opinion, we all talk about inflation nowadays and it's not far fetch to say that that amount isn't a lot of money, it's not the 1800s anymore where that dollar and 90 cents can get you to 2 days, inflation has happened baby!!!
It's not "living" if you can only spend $1.90 a day, that's fuckin' surviving in hardcore mode.
It's also preposterous of us to divert from topic about finding a solution about poverty, the discussion was supposed to be about how can we alleviate the problems that those in the poverty line are facing, it's not a matter of what amount is considered poor or not because if that local currency's converted to dollar, it's still going to $1.90.
In regards to solution for poverty, US can easily end the poverty and housing problem in their country by getting a small chunk off their military budget and allocating it to the stuff that needs the money. If we're talking in global scale, international cooperations between nations that have an altruistic intentions is the best way to go, no politics, no corruption, just pure and unadulterated altruism to help the poor.