You know where I stand on this sulfur,
I’ve got a small shop, with limited stock, and limited means to take part in the economy. I really prefer people exploring and finding smaller shops, but at the same time I’ve seen some small shops with what seems like very random pricing / no market research.
I have to agree with @anon73404375 that undercutting with unsustainable prices will be, well, unsustainable in even the short term. I also agree with omni that hand-posting 300 item prices per day would require a spartan dedication 
to your shop for the larger markets, and marketing alone should not necessarily be a full time job.
My marketing mainly consists of throwing random oorts with starberry stews and generally trying to be helpful when i see someone who needs a pointer. All my contacts are personally made, and this works great for a small store and is where I derive my pleasure from. For larger stores I simultaneously see the benefit of such a system as well as the negative impact it could have on newcomers.
As with everything added / changed / kept so far in the game, adaptation will be key and I’m sure good shopkeepers (whether they are big or small) will find a way to benefit from whatever is or isn’t introduced, would just be sad if something like this stopped people from exploring.