> The 68030 does look like a curious choice for a machine launched in 1988.
GP is exaggerating. Spark and MIPS were more expensive machines for a different market NeXT wanted a toe in but was merely straddling; business and education were NeXT's target markets. The 68030 with a math coprocessor was bleeding edge in 1988. Sun released a 20MHz and 33MHz 68030 Sun-3x in 1989, a SunOS (UNIX) workstation.[1] Apple released the 68030 Mac SE/30 (16MHz) in Jan. 1989. There was absolutely nothing wrong with the 68030 in 1988/1989. If anything, NeXT was a little fast out of the gate with the 25MHz 68030 in 1988.
They developed a dual-CPU prototype box based on the 88000, circa 1992. It was never released - the company was bought before it advanced past the prototype stage.
They also had a prototype laptop, although I don't know for certain which CPU it was based on. Because the existing battery technology couldn't provide enough juice for reasonable runtime, it was going to be a plug-into-the-wall design.
They gave up on the 88000 the same time Apple did (yes it was considered at Apple too) and is directly related the IBM/Apple PPC partnership and Apple’s insistence that Motorola being a second source for the PPC. It was really Motorola that gave up on the 88000 and not Next.
NeXT wasn't bought until late 1996. That didnt kill the RISC project, what happened is the company dropped all hardware and became software-only (primarily on top of x86 boxes, but some lower-level pieces ran on HP and SPARC).
As part of a project code-named "Jaguar", Apple did consider using a Motorola 88K variant as their future RISC-based hardware, but it was short-lived and they moved on to the POWER Architecture. In 1991, Apple, IBM, and Motorola formed the "AIM" alliance with the goal of creating a Common Hardware Reference Platform (CHRP). This led to the PowerPC architecture, which included most of the POWER instructions along with some additions and deletions.
Wikipedia says that they considered the Motorola 88000 but with a source that I've not been able to track down.