Most teams don't need a test platform — the threshold isn't test count, it's multiplication

I keep seeing "we have 500 tests, time to build a platform." I don't think test count is the trigger.

The thing that breaks the CI model is multiplication, not volume. Three browsers × two environments × a suite of forty cases is 240 runs from one definition. A CI job was designed to be one unit of work, so that expansion either serialises and blows the wall clock, or fans out into 240 jobs competing for a shared browser container — and those failures look exactly like flakiness, so you spend months chasing the wrong problem.

Below that threshold, a well-organised repo, a fixture layer and a CI job on merge is genuinely the right architecture. CI already is your control plane: auth, queueing, workers, artifacts, a UI. Reimplementing it is a waste.

Curious where others actually hit the wall. What's your multiplication, and what broke first — wall clock, or contention that got written off as flaky tests?