[viraptor]

You don't have to set up local mirrors. You can start the build with periodically-saved node_packages, or if you're using docker "ADD packages.json, RUN npm install", or commit vendored modules, or do one of thousand of other things.

For some companies release just means another merge to master, so they are doing tens/hundreds releases a day.

Once you do enough development that this matters, you're going to be doing caching or you'll be wasting money on waiting and bandwidth.

[LtWorf]

Yes you CAN do all of these things, but do people do them?

Consider that for developers a slow build = break time. https://xkcd.com/303/

And just running npm or pip at every turn is easier than setting up all of that, so there needs to be a push to do it. And the server of those entities seem to be able to deal with the load.

In my first job we had autoscaling cloud servers that took 30-40 minutes to be operational. I told my boss we should have pre-created an image instead of installing and compiling dependencies when we started them. But he said it would not be agile.

[viraptor]

> Yes you CAN do all of these things, but do people do them?

Yes, they do. Mostly as a result of looking for infra savings, optimising job time, improving reliability after some process fails when npm is down. It takes some longer than others. It's not necessarily devs that will do it either.