While this is technically true, it's practically false. I got NeXTstep 3.3 running on a machine in the office by building it from the parts of no less than 4 other machines to get the system to meet requirements. And then it was only in (2-bit) grayscale mode.

Other than hardware compatibility, the OS and Objective-C + InterfaceBuilder development environment was far ahead of the mainstream.

There were a few vendors who sold "certified" NEXTSTEP compatible PCs. They were more expensive than a generic clone PC, but far cheaper than the NeXT hardware. This eliminated the guessing game on device support and typically the component quality was better than generic.

Had NeXT's software pivot been more successful, there would have been more incentive for hardware vendors to pick up DriverKit and write a driver for it.

They were still aiming for high quality, when there should have been an emphasis on quantity.

The implication seemed to be that Nextstep required some inherently expensive hardware to run which it didn't. If in some parallel universe Microsoft had come up with Nextstep, they could have launched it as 'Windows 95'.

The original version of NS for PC (3.1) required 16MB RAM and recommended 24 (32 in 3.2). The software itself cost $800. In 1993-94 there was a massive RAM shortage caused by a factory fire in Taiwan. RAM spiked to over $50/meg. The additional RAM to run NS alone would have been worth on the order of $1000 even in 1995 by which time prices had gone down.

All told, a NS system would cost around 3x the cost of a Windows system.

Yes, this is all true if I'd said 'NS 3.x as it was then, developed by Next, could have been a drop-in replacement for Win 95'. Which I didn't.

No way. Even if Microsoft had been prepared to throw out Windows 3.1 and DOS compatibility (or engineer it in at substantial expense), NeXTStep would never have run acceptably on the low-end target machines.

It was a decade after the '95 release before optimization and hardware advancement had a NeXTStep-derived OS running 'snappily' on consumer desktops.

Nextstep ran on 68030s. Had it been a Microsoft product (since the late 80s) there's nothing inherent in it that couldn't have made it a consumer OS by 1995.

I think one of the problems is the RAM prices back then, which also affected Windows NT sales. 4Mbit DRAM chips was for example costing more than $10 a piece.

That's true but the original Next machine shipped with 8 megs which by 1995 was the recommended amount for Windows 95. There are lots of reasons Nextstep was a commercial failure, I just don't think 'hardware requirements' is fundamentally very high on the list. 1995 was just at the beginning of a rapid decline in DRAM prices, to boot.

MS spent a lot of effort trying to fit Win95 into 4 megs for a reason. I don't think NeXTStep with only 8 megs were a popular configuration, many was upgraded to 16 megs.

Win95 didn't fit in 4 megs all that well. But that's neither here nor there since we're in a parallel universe in which MS started working on Nextstep in 1985 and released a consumer OS based on it in 1995. This seems totally plausible. Next Inc was never really making a consumer OS. In 2007, Apple shipped a Nextstep derivative that ran in 128 megs while its desktop (and consumer) counterpart wasn't really happy with anything less than a couple of gigs.