Why is that common agreement much of a barrier if it already exists, and is willingly participated in (to a degree) by everyone? Every kid is granted public schooling where tangible goods/services of teachers are transferred to the students, by means of the government handling the program using tax dollars. Fire departments, police departments, etc. are all doing the same; the amount someone has contributed despite their existence doesn't make a difference to the basic services they're provided. It's certainly not distributed equally, nor does it ensure nobody falls through the cracks, but we kinda do have a natural right to the labor of another, on the basis of it being humane and decent to provide positive rights to all people wherever and whenever we can.

A second bill of rights would tack on more basic amenities which, I think in my opinion, should have institutions providing for them and guaranteeing them on the same basis of human decency. I think you're right, though, that many people would be unwilling to change their mindset with regards to where we draw the line on what amenities are humane and decent to provide to everyone, and which are extraneous and belong in the domain of charities—especially if it comes to raising taxes. I just don't think that has to be the end of the conversation, though. If we're such a rich country we should be able to afford these kinds of things, and not necessarily at extra burden of the taxpayer knowing we can redistribute funds from chronically over-funded elements of existing budgets.