Sad to say, this is a global problem. Your frustrations are shared by students, instructional staff, and management staff at every ARTCC in the US, and probably most other countries as well. Your points are spot on. Have you addressed your questions with your TA? If no satisfaction there, have you addressed your questions with your ATM and/or DATM?
If I can offer a glimmer of light -- just Saturday, VATUSA announced a new Basic ATC training program has begun development to (at least initially) help get folks from OBS to S1. It won't be ready for a few months, but work has begun. However, that just pushes the bottleneck up the line, at least temporarily, I'm afraid. But it's certainly better than nothing.
From what I can tell, ZAN is in about the same boat as most other facilities. 3 Instructors plus 3 Mentors to 27 students. Actually, 4.5 to 1 is a great ratio, but all 3 of the instructors are staff as well (ATM, DATM and TA). Providing training to students is only one (small) facet of their job duties.
We are all volunteers, and ratings take time. We are doing the best we can. That said, all any of us can really offer is encouragement not to give up, stay persistent, stay focused on your goal, and fight your way through to become part of the solution (become a Mentor, then Instructor) and help us.