There was a market starved for a stable, high quality and responsive operating system that would run on the x86 hardware that was abundant everywhere. Windows wasn't it, yet; recall this is years before XP, and Windows 98 was an unstable mess while NT was slow.
A little search gives a reference: https://web.archive.org/web/20131109045719/http://www.intern...
MacOSX would be really different today if it were based on BeOS instead of NeXT...
What NeXT brought was exceptional developer tools, not to mention Steve Jobs.
No Steve Jobs likely would have meant no iPod, iPhone, etc.
Linux had a similar problem but had the advantage of open source. Random people would cobble together support for things and stick it online.
I get it, many times I have seen stuff that is function all but very slow, considering Haiku can run fine on a Pentium 2, I can see why they wouldn't want that.