When it came to OS development Apple was a hot mess back in 1993: "Pink/Taligent" was falling apart (and the successor project, Copland, likewise turned into a debacle], and the PowerPC transition was sucking up tonnes of engineering talent just making the old system work seamlessly on the new hardware. (And of course there were those other interesting dead ends like A/UX floating around and muddying things even further) If you'd tossed NeXT into the mix back then it almost certainly would have fallen down a black hole of suck and been lost forever.
One of the major factors holding back Unix-based systems at the time was the extreme licensing costs. In 1992 NeXTStep 486 cost $995, which was a fairly typical price for a PC Unix distribution. (In fact it was somewhat on the cheap side.) NeXT might have been able to sell it for *somewhat* less, but all versions of NeXT/OpenStep before they started calling it "Rhapsody" were based on Pre-BSD 4.4 lite UNIX code and technically were bound to pay royalties to AT&T. Rhapsody was basically the alpha/beta testing period during which all the NeXT-specific code was forklifted over to a new royalty-free base OS distribution which borrowed heavily from NetBSD and FreeBSD. (They retained the Mach microkernel, but there to they had to "sanitize" all the low-level interfaces.) I of course have no idea how much each NeXT station with the OS bundled cost in licenses, maybe it wouldn't have necessarily been "prohibitive", but when you factor in the system requirements for NeXT to run well (8MB was a bare, bare minimum in an age where Apple's highest-volume machines were LCs with 2-4MB of RAM and hard disks far too small) and the presumptive requirement to incorporate backwards compatibility with the legacy OS it's extremely unlikely any NeXT-based OS would have appeared before 1997-98 at the earliest.
One of the most critical innovations during the transformation of OpenStep into OS X was the Carbon APIs, which gave developers for the Classic OS a method for forklifting their applications over to run on the new OS "natively" with relatively minor changes compared to rewriting it entirely for OpenStep. OS X almost certainly would have failed if not for the Carbon strategy; it certainly might have been possible for Apple to do a quick shovelware port of NeXT onto the early Power Macs (it *never* would have run at an acceptable speed on any 68k Macs; it was generally considered sluggish on even the best NeXTstations) in which the Classic OS would have run in a "penalty box" similar to Classic but it probably would have gone over like a walrus pole-vaulter. Say what you like about Windows 95, it actually for the most part ran legacy Windows programs *better* than the previous versions.
One of the major factors holding back Unix-based systems at the time was the extreme licensing costs. In 1992 NeXTStep 486 cost $995, which was a fairly typical price for a PC Unix distribution. (In fact it was somewhat on the cheap side.) NeXT might have been able to sell it for *somewhat* less, but all versions of NeXT/OpenStep before they started calling it "Rhapsody" were based on Pre-BSD 4.4 lite UNIX code and technically were bound to pay royalties to AT&T. Rhapsody was basically the alpha/beta testing period during which all the NeXT-specific code was forklifted over to a new royalty-free base OS distribution which borrowed heavily from NetBSD and FreeBSD. (They retained the Mach microkernel, but there to they had to "sanitize" all the low-level interfaces.) I of course have no idea how much each NeXT station with the OS bundled cost in licenses, maybe it wouldn't have necessarily been "prohibitive", but when you factor in the system requirements for NeXT to run well (8MB was a bare, bare minimum in an age where Apple's highest-volume machines were LCs with 2-4MB of RAM and hard disks far too small) and the presumptive requirement to incorporate backwards compatibility with the legacy OS it's extremely unlikely any NeXT-based OS would have appeared before 1997-98 at the earliest.
One of the most critical innovations during the transformation of OpenStep into OS X was the Carbon APIs, which gave developers for the Classic OS a method for forklifting their applications over to run on the new OS "natively" with relatively minor changes compared to rewriting it entirely for OpenStep. OS X almost certainly would have failed if not for the Carbon strategy; it certainly might have been possible for Apple to do a quick shovelware port of NeXT onto the early Power Macs (it *never* would have run at an acceptable speed on any 68k Macs; it was generally considered sluggish on even the best NeXTstations) in which the Classic OS would have run in a "penalty box" similar to Classic but it probably would have gone over like a walrus pole-vaulter. Say what you like about Windows 95, it actually for the most part ran legacy Windows programs *better* than the previous versions.