My daughter wet her pants until she was four! I thought I was going to lose my mind at the time. I can honestly tell you that bribes and fits don't work.
What works is when they have some place they want to be - like a pre-school - and they can't be there if they are wetting their pants.
HOWEVER, your son may be having a blood sugar issue to pay attention to: a drop in blood sugar will cause the bladder to let go. Having snacks around all the time (low sugar) will help this. Making sure he is getting enough protein and fat, plenty of fruits and vegetables will help this.
Then: put on a pull-up for safety. He may not want one, but give him the choice: the pull-up or the potty. He may be able to make that choice... but then again....
Learn from MY mistakes: My daughter had a daytime peeing problem and was not dry at night. I saw a doctor when she was 7 (yes, 7!!!) who told me the blood sugar trick. I started paying close attention to giving her high protein, high fat snacks both during the day and before bed and all of her symptoms went away.
Focus on: Cheese, meat (if you eat it), nuts/nut butters, avocados, fresh fruits and veggies. Avoid processed foods and high sugar foods. Go to the whole food stores for sweets that are made with unprocessed sugars, but don't serve lots of them either.