Before I get to where I THINK your big problem is I trust that when you rubbed... buffed to no avail you are talking about rubbing and buffing off all the excess oil at the time of application and not now, a year later.
Oil finishes, Danish oil included, is not a building surface finish, it is a finish meant to soak into the wood and cure there, with no real build up on the surface of the wood. Try to build an oil finish and most times it gets just like what you have now.
Which leads me to what I think is you main problem. In a word, plywood. A nice very thin piece of birch veneer laid over a non porous glue then some other wood and glue layers.
The key words here is non porous glue. There is, for all practical purposes, no wood for the oil to soak into. All it can do is sit there on top of that non porous layer of glue and sulk.
Your bad experience with oil is most likely due too a miss application of the finish.
My suggestion. Get a lot of mineral spirits and rags and wipe off all the oil you can get off then apply a real surface finish. Though, after some dedicated wiping, you may end up with a serviceable surface. Who knows.
No, in the case of plywood, while performance may be marginally better, it's still a miss application and will probably give you the same problem.