Here are my suggestions for increased participation. I don't have all the answered but have been around the block a time or two.
1. Your HS coach needs to be involved in your JR high or kids clubs. He needs to start building a bond with the kids. By the time they get to HS it's too late, wrestling is too hard for the majority of the kids to start in HS. Kids will try things when they are younger they will not as they get to HS. Too many beatings and they get more violent the older they get.
2. You need to have a JR high or kids club program to feed your school. (I guess that goes before #1). Name all the top programs with good participation and good year over year results and they all have good feeder programs. Colby, STA, Lansing, Wichita Heights, Andale, Goddard, Norton, Hoxie, Chanute, etc.
3. You need leaders in your top kids, someone others look up to.
4. Create something positive. Kids want to be a part of something that makes them feel wanted.
5. Don't be afraid to let kids work with other clubs, or teams. Of coarse not during the HS season, but some coaches don't want kids working with "outsiders" afraid they might see their secrets or want to leave. It's actually the opposite.
6. They need to wrestle more that 3 months a year and coaches from HS or club or something need to provide leadership more than 3 months a year. Freestyle, camps, off-season workouts, etc.
Just my thoughts, but think of any top program and they have this. On the contrary look at any program struggling for numbers and I bet you they don't have a least one if not more of these factors.