The question one should ask is: what $hot_tech can we adopt without the product becoming significantly worse than with $old_tech? That is, which things do we adopt only or mostly to make the project or company attractive to work with or invest in?

Saying “why would you ever do that rather than building the solution the cheapest and with the lowest risk” doesn’t fully appreciate the importance of attractiveness.

I’m selling my hours of work time for a salary, fun, and resume points. My employer pays me in all 3. I’ll always push for $fun_tech or $hot_tech despite it not always being in the short term interest of anyone but myself or my fellow developers. I’ll keep justifying this by “if we do this in $old_tech then me and half the team will leave, and that’s a higher risk than using $new_tech”.

(By tech I here mean things like languages and frameworks not buzzwords like microservices or blockchain, ai... )