Yes, hardware has limits and you just cannot have a single machine with unlimited number of cores and disks.
But as the article mentioned, NewSQL is already there. DBs in this category has actually been awhile. I think Spanner's paper was 10 years ago. And it is ubiquitous across Google. So let's just accept that we should think things differently in 2022. Distributed RDBMS is already a thing, used in production, in many companies. Like TiDB(https://github.com/pingcap/tidb) mentioned in the article, Square already uses it to replace some MySQL's use cases (https://www.youtube.com/watch?v=TjqL50qzy3A).