A team doubled their CI machine size and set workers to 16. The suite got slower and started failing tests that had never failed. They concluded Playwright did not scale.
Playwright scaled fine. They had passed the optimum, and past the optimum every additional worker makes things worse in two ways at once.
Why more workers stops helping.
Each worker is a browser process. Browsers are memory-hungry. When workers exceed available memory, the machine swaps, and everything slows down at once rather than gracefully.