People have been wanting the mythical xMac for literally 18 years. Making a cut-down version of the Mac Pro saves Apple very little money, therefore it would save customers very little. What do I mean by this?
If you cut the eight slots of the Mac Pro down to two or three or four, that saves Apple maybe $5-10. PCIe sockets are cheap. If you cut down the power supply to 600-800 Watts, that saves Apple maybe $30-40. If you cut the ram sockets down from twelve to six, you save maybe $3-4 dollars. A smaller case, maybe you save $100.
So Apple saves a couple few hundred dollars, and your cutdown Mac Pro is at least $5,200-5,400, somewhere in that neighborhood. Who wants that?
The small tower isn’t going to happen. People want it for $2-3k but that’s not a profitable or viable product for Apple. Customers just wanting it aren’t enough, otherwise we’d already have it.
Especially those coming from the PC side, they always want a cheap mini tower. But Apple doesn’t do cheap anything. Not enough people would want an xMac at the price Apple would have to charge to bring it to market. That’s what I see anyway, ymmv.
PS Note I don’t say I wouldn’t want one; sure I’d love a smaller Mac Pro for $2k or $3k, even if it didn’t have high core count Xeons available. But I’d also like a 5” iPhone SE Pro for $499. Apple would need to sell it for $849-$899. So yeah, I understand why Apple won’t make those, even though I’d really, really like them