That happens very rarely with our dozens of transitive dependencies. What are these packages that cause trouble often?
Still, it doesn’t have to happen often to be a serious hindrance to either developer productivity or your business. Imagine trying to roll out a fix for a production outage only to find a random transitive dependency has started breaking your build. Now your outage is extended to the duration of debugging and fixing an unrelated and avoidable problem.
Because you don't do ml. My requirements.txt is useless in 6 months because the transitive dependencies all have incompatible versions of common libraries by now
Maybe you’re using recent less-stable projects? I found that the main ML packages rarely break things without months of deprecation warnings.
My time and the time of my peers is too valuable to be debugging minor incompatibilities between a library 5 layers down the transitive dependency stack because versions aren’t pinned. It’s too important that if I go back to a 3 year old checkout of the code that it still runs and isn’t a wild goose chase of running down bugs and library incompatibilities.
You can always upgrade overzealously when dependencies are pinned, falling back to the workflow you’ve described, but the inverse isn’t true. If your tools don’t allow you to pin, you’re signing yourself up for churn at unknown and unpredictable times.