It seems to me that the programs that have success with fewer miles are the ones that never really had larger amounts to begin with or maybe just didn't have the athletes that could handle college level training programs. I'm sorry, but if you are "racing" 8k-10k at a higher level consistently, 50 miles a week won't get you through the competitive season at your best the last month, conference/regional/national meets.
That being said, as a coach, I would certainly be willing to modify for various ages and talent levels depending on the individuals rather than lumping them all into the same program. I can't see an 18 year old average incoming freshman doing the same volume, intensity and quantity as the 22 year old all american. I've coached long enough to know a talented underclassman can achieve as high as an experienced upperclassmen on race day with modified training programs appropriate for their level of readiness. You don't want that talented pony tired in November.
A good coach has to be a good communicator about this openly and consistently and have the ability to process all kinds of feedback. Ideally, if this can happen, he/she can maximize the potential of the team each year and have a progressive program that athletes understand and buy into. I just don't get the one size fits all mentality. Personally, I was more of a 800/1500 runner that loved to compete in cross country. I just couldn't do the mileage/volumes that the older guys could for about 2 years. Nor was I able to compete at their level without the 2 years of consistent, injury free training needed to adapt to that level. Luckily, my national champion coach knew what he was doing and knew how to build a sustainable program given the limitations he had on recruiting, scholarships, budget etc... I was lucky to have him as my coach and be a part of a program that believed in developing talent through hard work. As a result, I learned a great deal in my time with him because I spent a lot of time in his office getting answers to the "why" of what we were doing rather than just the what and how.
From there, 28 years later, I'm still doing all I can to learn and improve the design, delivery and assessment of the program. That's what it comes down to if you want to know how good you can be, now as an athlete and possibly in the future as a coach who wants to help others find out how good they can be.
Now go invest in yourself and spend some time learning from each other during this transition. If your coach is athlete centered rather than an egomaniac, you'll have fun working together.
Best of Luck