They're probably immune for a while because they're probably using a long term contract, but when it comes time to renew they'll have to offer close to market price to convince the manufacturers not to use that fab space for more profitable memory.

How does that make a difference? It's not like the price change is on DIMMs. The price change is on the DRAM, which is a commodity item. It's not like someone is going to discount it if you tell them "nah, I'm going to solder this one to my SoC".

If Apple is insulated it is likely because Apple signs big contracts for large supply and manufacturers would prefer to be insulated from short-term demand shocks and have some reliability that their fabs can keep running and producing profitable chips.

Perhaps on the same package (stacked) but absolutely not on the same die.

Which Apple product is this? Memory dies and logic dies require entirely different factories to make, so I doubt this SoC exists.

eDRAM is absolutely a thing. The argument against it used to be that it had higher cost per bit, but who knows whether that's true anymore with the current bottleneck in dedicated DRAM chip production.

As an aside, if DRAM costs stay higher we might also see renewed interest in other memory technologies (especially persistent ones) such as phase-change PRAM and magnetic MRAM that sit between DRAM and mass storage in the memory hierarchy.

I also had that misunderstanding, so after seeing this comment I looking up info. In this article you can see the xray of the m1 chip composited onto the photo of the chip, which has external memory components. You can also see in the architecture diagram that the memory is attached from outside the area where the Fabric, CPU, GPU, NPU, cache, and some other unlabeled things are located. https://www.macrumors.com/guide/m1/

And in this article you can see a photo of the memory chips attached outside of the Apple component https://www.gizmochina.com/2020/11/19/apple-mac-mini-teardow...