Hate to break it to you but the Next Cube was neither the first or last computer to let you add cards or storage, and the cards it used were a completely different form factor to the PCIe cards that people want today and ISTR that the storage was a brick-sized Magneto-Optical drive which was about as unlike a SSD as you could get. As for the Trashcan: the only upgradeable thing about that was the RAM - it had a single, proprietary SSD card and - just like the Studio - you were expected to use external Thunderbolt devices for all expansion.
If by "adapt" you mean make something a different size with different cooling requirements and taking radically different-sized components and then wonder why it's now a totally different shape - have fun.
OMFG NooOoOOZ! The NeXTdimension was the greatest graphics card that ever existed. The only reason NeXT had to drop everything and do a reverse takeover of Apple instead, was due to their slight delay in releasing the NeXT Sphere! It was floaty and would've only cost $125K 1980s dollars - that totally would've saved them.
OTOH it's entertaining seeing Apple's everythingOS APIs are still full of NX_ and NS ... it's roughly 40 years later at this point. And... every OS variant Apple is running across all their devices, is essentially NeXTSTEP but with 999 layers of crap wedged on top of it, because it's better that way!
The Mac Pro, I guess it's dead now? But it goes to sleep for a decade and then the Cheesegrater tends to wake back up. Who knows, It's been a good 6 year long run with 7,1 - still use it, have 768GB RAM in it ... in single core it's ancient tech, it eats power, but the 28 core variant is hitting 22K multicore on Geekbench 6, vs. roughly 27K for a Mac Studio M4 Max. Not bad for 6 year old tech, which was an old CPU at the time Apple released it. On the third hand, the price of a loaded Mac Studio is significantly cheaper. I'm unclear on the purpose of the current "Mac Pro" since they've kept the nice Heavy Metal sculpture case, but... it's just a PCIe slotbox which obviously is not helping Nvidia cards do anything useful.
Also, I'm watching people on this site and in reviews posting how exciting Thunderbolt 5 SSD RAID0 is! OMG. But... 6 year old tech using PCIe 3.0 and RAID0 Sonnet cards is going a whole lot faster. The bleeding-edge blazing fast speed enabled by RAID0 over TB5 is kinda ... meh, seriously? A lot of steps sideways but extremely underwhelming. I guess this is the only remaining upside of AS Mac Pro since it can't use graphics cards. 😐
IDK, Been on PowerMac, Mac Pro since the dawn of time ... but at this point daily driver is a Mac Studio, actual workstation is an HP, and Mac Pro gets repurposed a lot and runs a boatload of software which will never be updated for Apple Silicon. It's a beautiful artifact, and I guess within another 6 months or so if the current RAM prices keep increasing, even with DDR4 RAM it'll be worth about as much as I paid for it brand new in Dec 2019 🤷♂️
Strange days