I think Sony are gearing up for a price drop across all their PS branded hardware:

Yesterday, Sony Interactive Entertainment has changed the model number of the Jet Black PS4 Pro in Japan from CUH-7000 to CUH-7100 as discovered by the Japanese website 4Gamer.

The upcoming PS4 Pro “Rathalos Edition” coming with Monster Hunter World also features the new model number.

4Gamer inquired with Sony Interactive Entertainment Japan and Asia on the reason behind the change, and the house of PlayStation clarified that the new model number was required due to an update in the internal components of the console.

That being said, they also made sure to specify that there will no change in actual features or specs for the PS4 Pro.

This change is in line with Sony’s model numbering standards, with incremental alterations in the second digit of the number indicating minor hardware updates that have no influence on the console’s performance and looks.

If you bought a CUH-7000 PS4 Pro, you don’t need to worry, as your console is not becoming obsolete.

Normally this kind of change is made during the process of reducing the production costs of a console, with new parts that are cheaper to manufacture being swapped in to improve the margin per unit sale. It’s an entirely expected procedure that is often done several times during the life cycle of a game machine.

https://www.dualshockers.com/playstation-pro-hardware-update/

I don't think it would be immediate. They'd want to real extra benefits from selling a cheaper version for the same price and THEN drop the price when ... let's say, a new console drops.

New console? As in PS5, or a PS4 revision?

Aaaaannnddd... They tell us nothing about the specifics of the "hardware upgrade".
Just a ramble on what we already knew about in regards to the model number scheme.

Sounds more like a cheaper revision like the last wave of PS3's were rather than an actual upgrade. More of a cost saving thing with smaller and cheaper parts (possible die-shrink?). If true then the regular Pro's while being the same, might be preferable for some. Though that's more of a picky personal preference thing.

I just got a free PS4 Pro the other day. I haven't hooked it up yet but I will once I get a new game. Hope there's a noticeable difference between my reg PS4 and this.

They do tell us that it has no influence on specs or performance. So it's irrelevant anyway.

May not have new features but improvements in design and fabrication could mean increased reliability, lower power consumption and cooler running. Not saying it will but its a possibility.

In case they need to drop the price if the X1X starts gaining too much momentum. 

my thinking:

They drop the PS4pro 50$ this holiday.
PS4pro @349$ vs Xbox One X @499$.

Then in 2018 announce that they are keeping the 349$ price point.

As usual the new console will probably be more silent, less power hungry and cheaper to produce.

I’m sure they’ll drop the official price to 349,- coming holidays. It’s the perfect way to counter the X1X plus they already had such a price drop through days of play.