Well, the answer entirely depends on how we define “adequate.” Some people are quite pleased with ERPNext’s capabilities as-is. Others less-so. My personal opinion is it’s okay with inventory tracking out-of-the-box. But inadequate in terms of forecasting and capacity planning.
I’d say adding all the capabilities you listed could easily take 6-12 months of development work. A bi-directional Quickbooks integration is no easy task. And beefing up ERPNext’s planning capabilities is a huge undertaking as well.