Most of the replies are tackling Kubernetes from a technical perspective so for a people perspective, I can try to explain what might be a logical progression that I've seen.

A startup that grows to have hundreds of developers might transition from running managed VMs to "the cloud". One team sets up the network (virtual networks and some subnets).

As new employees join, they have no reason to interact with those teams who are effectively "hidden" so they deploy their stuff and perhaps wrangle with subnets and what not. Someone tells you that you need to attach subnet-a20w88vhuh4fuih to your resource and it will magically be accessible in the office.

Nothing is in charge of VM sizing so you've got people blowing hundreds or thousands on massive VMs when they're only using 10% of it and vice versa, teams whose application is choking but they don't really have a good mental model of say general purpose VMs vs memory optimised so they just bump up the SKU instead of being more efficient. This is happening everywhere as the company accelerates more and more.

It gets worse when you have a shared cluster say; for an entire team that is globally distributed and the new intern application is doing some weird O(n)6 computations and absolutely blowing the side out of every other resource you've got.

Now at this point, it's effectively a communication/culture problem but Kubernetes can "fix" some of these issues in a sense.

Network for the most part becomes abstracted away and what you're left with is defining security (what ports and protocols should I expect) on an application level, rather than on a security group level. It's kinda neat because these rules are localised to your application whereas they might have been configured manually in a cloud portal or via some terraform config owned by some team in the shadows.

Each of your deployed applications become their own isolated units called pods. A pod could be one or more containers but it's effectively a standalone slice of an application (ie the web frontend while a redis instance might be another pod). There are bigger abstractions to group application pods together but that's besides the point.

These pods get deployed to a cluster (a bunch of VMs) and cough "orchestrated" but the value here is that your containers might be running right next to some containers for the business team or the machine learning team and you would never know. You don't need to know either. The value, as foreshadowed above, is that if you're being a noisy neighbour, your container will either get rebalanced somewhere else or just shut down for exceeding memory usage.

I'm a bit flakey on this point but since each node in a cluster is a massive VM, there's no need to worry about over or underspending based on your computational use as well. You define the amount of memory you want to allow and you get matched to a relevant node based on how much capacity is available. As you gain more users, you just add more nodes. Before that, you might have been "reserving" say X thousand compute hours of certain VM SKUs or whatever. You might still do that but you could feasibly just have whatever your node sizes pre purchased making capacity planning pretty straight forward.

Generally, there'll be some team whose purpose is to manage said cluster so in a funny way, it somewhat revives the whole dev/ops split in that your compute team generally know the nitty gritty of networking and what not while your developers just deploy an application and it "lives on Kubes".

I may have a missed a bunch of stuff but hopefully this outlines some of the more "people" issues a bit? It's half and half useful but also it can be used as a technical fix to a social issue.