Most of the "Pay what you can" restaurants in the Raleigh-Durham area are associated with ministries that include campaigns for people to donate money to support the mission. None of these restaurants make money. All of them would go out of business if their ministry cash stream was cut. Less than than 10% of their patrons leave money. Effectively they are food banks with a restaurant atmosphere and serving hot meals. While these "Pay what you can" restaurants serve a noble social purpose as charitable entities they are not viable businesses.
And it is important to realize that a government model of socialism will also lead to the same problem. As Mrs. Thatcher once said "The problem with Socialism is that you eventually run out of someone else's money."
The problem with socialism, as with all other "-isms," is misunderstanding promulgated by simple catch phrases used to promote personal agendas, too often picked up and repeated by the poorly informed. All modern economies are mixed economies. The private sector manages some thing better than government, and vice versa. The goal should be to have both good government and a good mix .
Maybe the IRS can try out a "pay what you want" experimental programs just to get that old socialist ball rolling.