first, have you even talked with the kids about their feedback or are you just sitting there in a white coat doing preplanned workouts then looking at the equivalent of the clipboard criticizing the statistical outputs and the fact it's not gone to your plan? maybe this group needs a different plan. maybe this group isn't as serious. maybe this group needs more fun. don't ask us. ask them how the season is going.
second, did you internally scout people from the TF distance team or the other sports? like my school would be still trying to get that fast guy from baseball to join the relay on up to the end of the season. the astros started this season awful but churned the team with new players from AAA. i think sometimes coaches are so up their own tookus about rewarding doing their workouts they ignore help might be down the hall, if they cut the kids slack for being new.
third, is this you complaining they aren't great, or have only improved so much, or is this they are literally flat since race 1? if they are flat since race 1 that suggests to me you overcooked them in august. they might respond to backing off.
without athlete feedback it's hard to know if they are sick of you or unmotivated. if they are sick of you personally, drop the criticism, drop the routine practices, and make it fun.
if they are unmotivated but willing, take them to the track a few days where they can be monitored. i can goof off around campus where you can barely see me. but that only works if they are sincere but lazy as opposed to sick of the tyrant. if they are sick of you then they can slack and sulk anywhere, even under your nose.
fourth, if you are just the XC coach, maybe consult the TF results for the returning kids. did you get the TF distance kids? if not go find them. or maybe you did and it's just a slow group, as evident from TF times. at which point your job isn't to win area so much as coach them to some degree of improvement and happiness. and that might involve talking to them personally and figuring out the issues. a lot of the workout fetish on here assumes highly motivated already successful runners that you are just trying to maximize and chase big successes and college.
but if they really haven't been athletes much, your job may be more to find their internal athlete, their speed, their toughness. the kids playing team sports since age 5 know this stuff. but not someone who starts running age 14. kind of like we had this guy on our college soccer team who was super fit and hard working, just sloppy. i might need fitness work if i let myself out of shape in the offseason. but he probably needs technical work. horses for courses. and train to what those kids need. not what some good year with already fast kids needs.
last, nothing says you can't recruit from PE classes, the TF team, or other sports, hoops, soccer. scout around the school. i believe schools can have down years, but i also think there can be talent sitting around someplace untapped, too. if they stink that bad and don't care then sorry, any in shape soccer or hoops player can probably run that fast in their sleep on their baseline training.
that and my TF coach would grab the fast kid from the baseball team for a week if he thought he'd help our relay compete. last week of the season too. some of the barrier here can be coaches who fetishize their workouts so much it's deemed unfair to bring in someone who hasn't done them. i had a stupid hurdles coach who punted me for missing too many practices because i also did soccer -- but i was his best 300H guy at meets, and they were never any good at the event after. are you trying to win races or are you trying to aggrandize yourself and the importance of your practices?