Surely not less than 16GB, but due to all the problems RAM had, stopping its price drops or even increasing its price in the worst periods, we can be quite sure that if it won't be launched later than 2021, it won't have more than 32GB either.
It could work well both for production costs and devs' needs if the base model will have 16 or 20 or 24GB (at most, and less likely, maybe more likely for later base models) and the first premium model 24 or 32GB. Total, main + graphics RAM. I wouldn't rule out that on top of those amount of fast RAM for gaming and essential parts of the OS that must be quick to not become a bottleneck, it could also have 2 to 4GB of cheap and slower RAM dedicated to a cheap mobile secondary CPU used for lightweight OS tasks and services, HW supervising, security, communications, etc, whatever could be done slower without bottlenecking games. Such secondary CPUs are already used, and they already get dedicated cheap RAM on premium models, next gen they could have it on base models too.
In this case it could be 18 or 22GB total for the base models and 26GB for the first premium one (every launch model would have 2GB cheap secondary RAM), while later premium models could have 36GB total (4GB secondary RAM).

Taking into consideration that the gens seem to be getting a little bit longer as we go, if they dropped a PS4 Premium in 2019, making the gen 9 years total, then you just might see a 128GB PS5 in 2022, but there would be better ways to divvy up those funds instead of allocating so much to the RAM.

The only reason it would need that amount of memory would be if the system was going to be a virtualization server capable of running instances of the console on all the devices in your house.... at the same time. processor to go with it would need to be in the 5 digit region and not something like the Ryzen 25XX that it will more than likely have.

This amount of memory would be pointless... well it would have one point, make the system either completely unmarketable from a price point of view... or just be a box which happened to contain a massive extra compartment of unused obsolete DDR2 sticks of ram simply to be able to claim the system had that amount in it.

but how much is that mobile phone? You're looking at $580+ for a phone with that amount realistically, machines with outstanding amounts of memory are not the norm which consumers (especially ones with price in mind) would ever go for, if Sony was to try to push a system which was that far ahead in terms of storage it would have people shudder and think of the ps3 being totted as more powerful than supercomputers at the time it launched to justify its massive price point.

A moderately high end gaming PC right now could happily get by with 16/11GB memory and that's something which contains a 1080TI sure you can put far more system memory into a PC but very few games are going to consume more than 16GB of system RAM in the real world... keep in mind, that would be a PC containing a $600-700 graphics card... before adding in anything else to the case. It would be unsellable as a console.

things being capable of it and shipping with it are 2 different things, My PC is capable of having a Petabyte of storage, that doesn't mean that amazon sells PC's with a Petabyte of storage.

I'm just saying, does the store you purchased your laptop from actually stock ones which come with 32gb of RAM as standard?

They don't appear to sell 16gb ram sticks along with my GPU, but it is quite a simple upgrade and isn't much of an expense. True expense comes from the GPU, which is where most of my budget went into.

For the more expensive GPUs they of course offer 32gb RAM and even 64gb RAM to keep up. But with both GPU and RAM being upgraded, the price obviously skyrockets.

I'm guessing to the point where you could buy a stack of PS4's and X1's :D

I really hope Sony learned their lessons from the ps3 and avoid the "future proofed supercomputer" and stick with the PS4's mantra of moderately powerful all the curves in the right places type machine with a price point just as sweet as the performance, gotta find that sweet spot again and gamers will flock to it.

1.175 € with an i7-7700HQ and a Geforce GTX 1070. Moah Powah than an Xbox One X in a laptop! =D

It was on sale though. I think the normal price was 1.599 €. And yes, I know that's way way more expensive than a console can possibly be. But as I said, I expect the PS5 to release no sooner than 2020 and by then 32 GB should be the standard.

High end laptops that cost 3000$ - 5000$ don’t even have that kind of ram.

What y’all been smoking thinking a 400$/500$ Device would have that kind of ram?

And phones are more expensive than consoles...What the fuck even is this post LOL