assume you are referring to https://en.wikipedia.org/wiki/NonStop_SQL -- was not aware of it so thanks for bringing it to attention. first impression is that it was a technology way ahead of its times. in late 80s (and some would argue even recently), majority of apps can be run easily on monolithic/single-node SQL databases. they are not generating data at a volume that requires multiple nodes (in this case parallel computers) and user perception can indeed tolerate high latencies, manual failover and repair. we are now in a different era when it comes to data volume and user perception.

And if we are being honest not much has changed 99% of the projects still can run fine on monolithic/single-node SQL databases.