[bcocaTM]

Yet people use daily to manage 10k-100k+ servers/devices.

The term "scaling" has very different meanings depending on context and how one product scales is very different from another.

You could setup a context that favors push vs pull and vice versa, you can also see different products scaling well or not depending on slight variations in context and implementation.

[mianos]

I am highly dubious that it would be possible to manage 100k servers, specially to do interactions with large numbers at a time. The way tower collects results in a thread pool, assuming success, simply does not work at any scale. I tried and tried. I fixed many bugs and got to about 4000 hosts before changing to another platform.

If almost every server is reliable, I am sure it would work fine. That is not going to happen at scale.