Boring tech behaves in predictable ways. It’s a well trodden path others have evaluated, optimised, troubleshooted, and understood. Using tech that has been subjected to all those people hours of use means you’re less likely to run into edge cases, unexpected behaviour, or attributes and features that lack documentation or community knowledge. In other words, when something goes wrong, can you turn to someone or something?
There's sometimes something to be said about using technology that's been around for a while. Chances are, someone has run into the same problem you're facing and knows a solution or work-around.
This isn’t to say there isn’t room for innovation, or that staying put is a guaranteed recipe for success. What it does teach is that it pays to make informed decisions, and that often times the understood, reliable, boring tech will get you there over something new, shiny or propped up with marketing spin.
Also true, be mindful of the choices you make. New isn't necessarily bad, but it isn't always better.