TL;DR it looks like the M4 Mac Mini redesign is _not_ soldered onto the logic board. So instead of paying 6x street prices of similar SSDs, you can just upgrade it yourself with an SSD of your choice!
This is absolutely huge news. I wonder if Apple will do something similar for the Studio, Pro, or -- dare I hope? -- even the Macbook Pros in the future? I can't imagine allowing this 'trapdoor' of money savings is a huge problem for profits since most businesses would never bother messing around with warranties for a spec upgrade. But this is absolutely MASSIVE for consumers. Just put in a little extra work and you can save hundreds or even thousands of dollars compared to Apple's upgrade pricing, for a good enough end result.
Not to mention the fact that this must also save _Apple itself_ an insane amount of money for repairs! Instead of throwing away the entire logic board, the CPU, the soldered-on RAM, and the soldered-on SSD whenever any of those components fail, you can just replace the malfunctioning part. Who'd have thunk (other than, y'know, every single computer company from 1980-2015)?
I would also of course love to see this upgradeability return to RAM. I'm curious if anyone more knowledgable than myself might know if the SoC/Apple Silicon Unified Memory system makes that more difficult, or if we've just accepted it because Apple Says So.
And while I'm on the subject of non-upgradeable RAM: does anyone know why no SBCs, from Raspberry Pi to Orange Pearl Jam Cake to Milk, allow for upgradeable RAM? Surely it's possible in the SBC form factor?
The modules are proprietary to Apple because of course they are. So no, no easy upgrades unless and until someone clones the design and is able to produce them in enough quantity to be competitive on price - but even then it'll be more expensive than a commodity SSD of the same size.
Looking at the price difference between m4 and m4 pro I think they're not that worried about users "upgrading" SSDs. Also, good luck finding SSDs that match the speeds you get with Apple provided ones .. at reasonable prices. If this were a laptop I would worry about power draw as well.
Unless I'm mistaken, this appears to be a custom storage module, not available for sale.
So Apple gets the best of both worlds. They can keep charging their high storage costs, but they themselves gets the flexibility of easily upgrading storage due to having this as a module.