This is often a struggle I've had as an engineering manager (though also as an active individual contributor). When I push back on adding new components roughshod to a stack, its often framed as "not invented here" dogma. I certainly can do a better job at communicating my sentiments, because I can and do predictably come off as a "grumpy old man" in these conversations.

But more often than not, this feedback comes from engineers that a) have never been (as you say) bitten by complexity, or b) they aren't in the position to deal with all the negative consequences for those decisions.

There's probably some wisdom in letting your direct reports experience the kinds of failure in making these decisions, so they develop that sort of empathy, but the cost of that failure is sometimes just unacceptable for the business; especially in periods of cash runway constraints.