I think [MENTION=63508]Minigiant[/MENTION] hit the nail on the head with pricing, though I think the 2 gp/day hireling cost already *is* hazard pay.
I base that assertion off the BD&D retainer pricing.
One of the things I miss (and often still refer to) from the BD&D Rules Cyclopedia is the section on Hiring Retainers. Very worth reading [MENTION=54629]pukunui[/MENTION] if you have that book or a pdf.
Directly from that book, here are some cost comparisons...
Mercenaries: Individually, they cost 2-30 gp/month. For example, costs per month: footman 2 gp, heavy footman 3 gp, archer 5 gp, light cavalry 10 gp, dwarven mounted crossbowman 15 gp, elven longbowman 20 gp, heavy cavalryman 20 gp, elven mounted bowmen 30 gp.
However, in order to maintain your mercenaries' arms & armor in working repair you would also need to hire an armorer for 100 gp/month who could tend to all your mercenaries' gear.
Specialists: Specialists were significantly more costly. For example, costs per month: alchemist 1,000 gp, animal trainer 500 gp, armorer 100 gp, engineer 750 gp, magic-user 3,000+ gp, sage 2,000 gp, spy 500 gp (per mission, not per month), seaman - rower 2 gp, seaman - sailor 10 gp, navigator 150 gp, captain 250 gp.
It's clear the 5e hireling cost of 2 gp / day (60 gp / month) is extremely inflated compared to the BD&D costs.
Without knowing the expected wealth per level of either edition, it's hard to make any kind of mathematical inference about what the 5e cost *should* be, but treating the 5e PHB cost as the cost for hiring retainers for short deadly ventures of less than a week might make sense, whereas a lower cost might make sense if they're just there to keep watch, keep their armor polished, and fight in traditional armies for their feudal lord.