Yes, both. Indeed, the fundamental question is whether the costs of automatic memory management (be it tracing GC or refcount GC) are "worth it". But it's not

Yes, both. Indeed, the fundamental question is whether the costs of automatic memory management (be it tracing GC or refcount GC) are "worth it". But it's not always as simple as a monetary consideration, and even when it is, the monetary cost often involves way more than just dev time vs cost of computer (e.g., power, cooling, distributed cost over many end users, market applicability because of system requirements).