Mature, widely deployed technology is unexciting precisely because its failure modes are known. That knowledge is the product. A database in production for twenty years has had its edge cases found by other people, documented in answers you can search, and fixed in releases you can adopt.
Novelty has a budget
A team can absorb a limited number of unfamiliar technologies before operational load exceeds its capacity to learn. Spend that budget on the one or two places where a new tool creates genuine advantage, and take the well-understood option everywhere else.
Teams that spend it evenly across the stack end up expert in nothing and on call for everything.
The hard part is operating it
Evaluation focuses on how pleasant something is to write. Most of the cost is in running it: upgrades, backups, capacity, debugging at three in the morning, and finding someone who has seen this failure before.
For a mature technology all of that is a search away. For a young one it is original research, conducted during an incident.
Hiring and handover
Common technology has a deep pool of people who already know it and a much shorter ramp for anyone joining. Unusual choices narrow the pool and lengthen onboarding — a real cost that never appears in the evaluation spreadsheet.
Boring is not the same as old
The test is not age but whether the failure modes are understood and the operational path is well trodden. Some recent tools qualify; some long-established ones, in unusual configurations, do not.
Choose the interesting option where it is the actual source of advantage, and be relentlessly conventional everywhere else. That is what leaves enough attention for the part that matters.