Not true, they all did workstations.

https://en.wikipedia.org/wiki/SPARCstation

https://en.wikipedia.org/wiki/IBM_RS/6000

https://www.reddit.com/r/vintagecomputing/comments/1fz29tx/r...

https://en.wikipedia.org/wiki/SGI_IRIS#MIPS

https://www.openpa.net/systems/hp-9000_720_730_750.html

Apple (or NeXT) were never vertically integrated back then. In the last 6 years with Apple making their own CPUs for OSX you could call them a vertically integrated UNIX shop. Not minicomputer though, which is from my post you replied to. Apple was not a vertically integrated vendor that survived bottom-up attack, they attacked Intel from bottom up via mobile/smartphone cores in a similar way Intel did to the minicomputers.