It’s pretty common actually. A server buy can easily be an 8 figure deal, getting servers that turn out to be stupidly configured for your apps that your stuck with for 5 years is exceptionally dumb.
I should've emphasized lab before of homelab. Agree, doing a full stack hardware validation (managed to even get a full multi-vendor stack deployed into a Dell validation colo to do our internal performance test). Even then, we only ran out own performance tests, as we cared about our workload, not a generic workload suite.
Edit: Additionally, we only did that work on a single set of systems prior to purchase, not the systems post purchase, so 1 of N, instead of rerunning on N. It was presumed that performance would remain the same on same hardware configuration etc.