Hello I'm Neal and I am here to help resolve your issue. If I cannot help I will opt out and refer your question to another expert.
Based on your explanation, it would be worthwhile to replace the oil pump, if it was not run while low on oil or while the pressure was low then the rod and main bearings should be good and it is likely just a bad pump and replacing the pickup tube just helped a little by allowing more flow.
Replacing the oil pump is a pretty big job for me so I want to make sure it the most likely cause.
I'm not jumping right into replacing the pump because I'm a little puzzled by the fact that the light only comes on after driving for a while and that there is no valve noise.
Those two things are making me suspect that something else could be causing it. any idea what could cause the light to only come on after the car heats up and shouldn't I hear valve noise if the pressure is low ?