> the example I really wanted to use was people picking Go for their top-end, competitive-with-anything-in-the-market database.
You mean they're writing their own database? Why? That's a huge job and available databases are pretty good. There are multiple open-source choices, all of which work.
If they think they're going to compete with Oracle, they need to read the history of Oracle.
There are many workloads for which all available database engines are poor. If you have one of those workloads and the esoteric technical expertise, it is entirely plausible to improve performance, scale, etc metrics by 10-100x versus whatever is currently available in the market. 10-100x is qualitative if that is central to your business.
Of course, almost no one should attempt this. The number of people with the technical expertise to pull it off successfully is much, much smaller than the number of companies with workloads that would benefit from this.
It doesn't have to be an exotic workload. Sometimes the market is just full of weak implementations e.g. graph databases.
There are at least a dozen new databases in the market making decent money that were started this decade.
They're just not competing with Oracle.
A large part of success is picking a goal that is obtainable.