Of course those in poverty could sell their possessions - and often they do exactly that out of desperation - but what then? It is a short-term solution which will not pull them out of poverty, it will only reduce their quality of lives even further.
Also remember that modern consumer items are very affordable - those items you mentioned can all be purchased for less than the cost of a weekly shop - but that's not to say those who possess them earn enough to pay their bills and put the food on the table every month. I would like you to imagine what it's like to have just £10 a day disposable income, then you have the misfortune of an unexpected bill you cannot afford. Sorry kids, Dad can't afford dinner tonight.
Poverty is of course relative - but why is it useful, considering the wealth in the world (and particularly in Britain), to lower the poverty line to 18th century standards? ALL working people in Britain could and should be living comfortably in the 21st century.
A flat screen TV or games console for less than the price of a weekly shop? You shop in the wrong places me thinks, Waitrose prices tripled have they? Less mobiles means less ongoing bills. And you need to work on your budgeting expectations, £10 per day DISPOSABLE income is not poverty.