I felt her pain. This is the biggest obstacle to sewing for yourself. It is all fine, when you are with others that can help you tweak garments, whether it be a personal tailor or in a class setting, you have to invest time in the garment before you can have the fit you desire. Fit is a process, no matter ready-to-wear or custom.
Not everybody has a personal tailor, or like me, love to tailor my own clothes. That's why taking classes in person is so helpful. You have the chance to experience the process first hand with a guide to lead you and answer questions along the way. It's nice to have immediate access to the online sewing community to get your questions answered while knee deep in a project.
This is my take on the need for in-person instruction and training for better sewing.