Whenever asking "if I did X, would that let me get more of Y" Remember that Apple isn't driven by the modding community, they are just a bunch of old dudes riding some kid's idea to the bank. They build stuff that works, that is cheap, that max out profits.
We all love to tinker but you don't buy an iPhone if you are a tinkerer, there's not enough to tinker with. If I wanted to tinker I'd buy a thinkpad so I ca yank it open and reroute cooling systems and smear thermal paste all over everything. I buy a mac so I don't have to do that, so in the 99 percent likely hood that I'll break the device it doesn't happen.
Even if it saved space, Apple wouldn't do it. They like making you choose between your arm, and your leg. Plus it would cost money to get in to, to change the manufacturing process, ect ect. If you want more ridiculously overpriced memory, buy a bigger phone.