indeed but there is a fairly good chance the existing memory controller would handle it just fine since it's based of an APU that has the support for it, but even if it didn't, designing an already customized system around additional ram wouldn't really cause a significant increase to unit cost, just more cost for the R&D of the hardware to begin with, and a little extra on more circuitry and power distribution for the additional modules.
Point is, even if you gave it a really broad and generous estimation of final additional cost per unit, you'd only really be looking at $30-$35, and that would be *very* generous too.
There's a very good reason which i'm sure you'll understand and agree with, as to why they won't do this.
Simply because of balance, they wont put more ram into a system that would very much benefit from it (due to 4k targets), because they know the rest of the system wouldn't really be able to fully utilize it, and including it would also mean that somewhere down the line their next console would need to be significantly better to entice buyers.
No console manufacturer is ever going to release a system that's as cutting edge as they can possibly make it, because there would be no profit in it for them, which is why i'm a PC gamer, you choose what to spend, you choose how good or bad you want things to be.
Just CS go? a $50 second hand rig would suffice, want multi-4k gaming at smooth framerates, it'll cost you but you can do it, no waiting around, no "generation" and for the most part, plug and play upgrades.
Scorpio is, in my opinion, Microsofts bridge console between their Xbox brand and their windows brand, as it moves ever closer to pc, and evidence to me that they're slowly tapering off out of the console market while trying to take as many console gamers with them as they can - ultimately, it's a Microsoft branded, MS-Store locked steambox.
Not to mention that while quite surely Scorpio RAM could be faster than original XBOne one, it's even more sure that it will be current mainstream RAM, not exotic high-end one, so it will require current standard circuitry and controllers just like plain XBOne used standard stuff of its period (also custom chips, yes, but based on back then standard ones).
After all every market segment evolved in four years, so it's possible to get a boost for free simply staying in the same segment and gathering what these years brought to it.