I currently coach at the D1 level and recently began coaching a team this past XC season. Every year they were one of the last teams at the conference championship and regional meet. This trend stretched back over 20 years. Every. Single. Year.
In one season we became at the top of our conference in both the men's and women's side. Became regionally ranked and placed high on both sides. Are getting good recruits (couple girls running sub-4:50/10:40 out of HS/ boys running 4:14-18/sub 9:20), and are now in position to be a bubble team for NCAAs (close this year). Best seasons in over two decades.
So what changed? Well, of course the training had to change, but there was more to it than that. I made an effort to really believe in my team. Tons of one-on-one meetings with people when they needed it. Making an effort to speak to every single one of my athletes every day. Cheering on every single person on the team in a race or workout. Individualizing every single person's training plan going into the summer and through the season. Really encouraging group running even if some have to slow down/speed up. We let go of some people who weren't the best for the team culture and who didn't want to put in the full effort.
When I first came in, a lot of people told me how slow the process of changing a team culture can be. To an extent, I believe it. It always seems like an ongoing process and the moment you slack off is when it gets undermined. However, I feel like a lot of coaches try to ask the athletes to change the culture without themselves first leading the charge. A dysfunctional, low-self esteem group of college kids had a lot easier transition to success when they saw how involved their coach was this year.
Our team is one of the largest in the conference and also the largest in the school, so I get where you are coming from when it comes to unruly numbers. At the D1 level we get the extra-added benefit of having to deal with more big egos (yay). But you just have to try very hard to make a passionate, welcoming, motivational environment. That's what I sell to all my HS and JC recruits and a lot of them seem to really buy it. That's what I sell to my team and they bought in 110%. Our sport is very mental and relies on motivation. Losers have that stifled. You just gotta bring it out of them.