If there is a demand for commodities you can be pretty sure that in a free market this demand will be satisfied.
Of course, there will be a range of goods that the poor wouldn't be able to buy just like they can't buy now, but in a free market such goods will be cheaper and of better quality -- hence poor people will have better access and more options to goods than they have now.
I don't believe there are any government mandates requiring the provision of food and clothing by companies -- goods you actually do need to survive -- and yet no one is concerned that they are accessible to poor people (at least in North America) primarily due to the very high amount of competition in these industries.
I am not sure what you mean by: "prices would rise and wages decrease to a point where selling to the poor or poorer would not be economically feasible for any business whatsoever?" If you mean that prices for goods will be at a point where poor people, earning low wages, will not be able to afford them, remember that in a free market the general tendency is for prices to go down through competition. It is regulation that interferes with this tendency -- for example licenses, regulating entry into industries, etc. Here is what Roderick Long has to say on this issue:
"The principal cause of poverty is government regulations that legally prevent the poor from bettering their condition. Minimum wage laws increase the cost to businesses of hiring unskilled workers, and so decrease the supply of such jobs, causing unemployment. Rent control laws increase the cost to landlords of providing housing, and so decrease the supply of such housing, causing homelessness. Licensure laws, zoning restrictions, and other regulations make it nearly impossible for the poor to start their own businesses. Two examples: urban black teenagers have been prosecuted for braiding hair without benefit of expensive beauticians' degrees; and in many cities, a taxi license costs as much as $100,000. Such low-capital enterprises as hair-braiding and taxi service are a natural avenue for people of little means to start earning money and achieving independence; but the coercive power of the state prevents it."
Moreover, with more opportunities for profit, and no opportunity for government caused inflation, businesses are going to have to compete more vigorously for workers, meaning that the poor are going to have more jobs to choose from, leading to better working conditions and higher real wages.
As well, since in a free market people will be richer, more money will be given to private charities, which is a much more effective way to help the poor than government welfare, as these charities have to compete with other charities for lower overhead costs. Just think about how much the average dollar of tax money that is allocated for welfare that reaches poor people, versus the proportion of the average dollar given to private charities that reaches poor people.