Eg. Even if you buy the same hardware you can’t replicate production load anyway because it’s not being used by 5 million people concurrently. Your cache access patterns aren’t the same, etc.
It’s far better to have a fast path to prod than a staging environment in my opinion.
I find staging to be very useful. In various teams I have been a part of, I have seen the following productive use cases for staging
1. Extended development environment - If you use a micro-services or serverless architecture, it becomes really useful to do end-to-end tests of your code on staging. Docker helps locally, but unless you have a $4,000 laptop, the dev experience becomes very poor.
2. User acceptance testing - Generally performed by QAs, PMs or some other businessy folks. This becomes very important for teams that serve a small number of customer who write big checks.
3. Legacy enterprise teams - Very large corporations in which software does not drive revenue directly, but high quality software drives a competitive advantage. Insurance companies are an example. These folks have a much lower tolerance for shipping software that doesn't work exactly right for customers.
Like how much productivity is being wasted because their machine is slow.
$4000 workstations are cheap compared to staging.
The official reason (which was BS) was "to simplify IT's job by only having to support one model"
Often workstation class processors, like an i9 are the sweet spot, especially with ccache as only one file is being recompiled.
Servers often sacrifice single thread performance for many more cores.
For a lot of things, this makes staging useless, or worse. When production falls over, but it worked in staging, then staging gave unwarranted confidence. When you push to production without staging, you know there's danger.
That said, for changes that don't affect stability (which can sometimes be hard to tell), staging can be useful. And I don't disagree with a staging environment for your usecases.
That depends on what Staging is used for, if its used to run e2e tests, giving a demo to PMs etc, you can use Staging. For performance testing you can setup a similar env like Prod, run your perf tests and then kill the perf env or you can scale up the staging env, dont let anyone use it except for performance and then scale it down.