Former IT services firm owner here, I can confirm these statements and assessments. I always told my clients to go "semi-live" with their new systems before full blown deployment, even if that meant a small delay in overall implementation. It's better to crash a test system while your primary remains unaffected than to have your whole network down for extended periods when unforeseen issues arise (and they always do, makes me wonder why they are still "unforeseen")
still, can't wait to meet my tribe mates in Ragnarok