During the worst of covid I would sometimes get grocery orders and pick them up in the dedicated parking spots. Most times it was brought to me by people that appeared to be under 25. Several of the young guys would use boss, as in “want me to close the hatch, boss?”. It seemed like a generic term, one they threw out dozens of times a day, with no caste/power implications IMO. I hear it far less now (and don’t do grocery orders) so I assumed it was a slang term that had its day and was fading out.