It is clear that bearings like the footstep bearing where there is no wedge action are always difficult to lubricate. In engineering there are plenty of sliding bearings like the cross-heads supporting the little ends of the connecting rods in steam engines and double-acting marine diesel engines. All sorts of schemes were used to get the lubricant between the surfaces but mainly they depended on having grooves cut in the faces and drip-feeding oil into the grooves. It is just a practical matter that might be made easier by careful choice of the properties of the lubricant.
But it is wedge action that makes the plain bearing reliable and successful. The physics of the angled surfaces with one sliding is there to use to find out more about such bearings. In the journal bearing the two surfaces are wrapped round a shaft but, as the clearance is so small the physics is directly applicable. There can be no question that the Michell thrust pad is also a direct application of the physics. Let me look at the journal bearing first