A few thoughts:
- Just because no one complains, doesn't mean that you know what they're thinking. And I'm not suggesting that an appreciable number would quit because of drills. But again, at any age, motivation and effort and energy are all finite things. Make the to-do list longer and/or items more burdensome, and something falls off the plate.
- Team culture. Just because you've decided that it's part of your team culture doesn't mean that it's athletically valuable. You could make eating popcorn or singing songs or talking about particle physics part of the culture, too.
- "We coach that efficient is fast. Everything we do is geared toward being complete runners and self-improvement. They understand the value because they see the results in themselves and their teammates."
Sorry, but is just kind of meaningless gobbley-gook. What's a "complete runner"? One that does drills? Does self-improvement (whatever exactly that means?) require drills? They "understand the value" of what? If we're talking about the proven or evident value of drills, they surely don't know.
I've been running fairly seriously for nearly half a century. What is there? The enjoyment of running. And performance. One can SURELY enjoy running without spending time on drills. And if we're looking at the pie chart of what contributed to Susie beating Jenny's butt every race this year, that pie is made up MOSTLY of talent, volume, and quality (and maybe I'd throw in proper rest). The benefit of drills is a tiny sliver, if it's there at all.
So again, you can make anything part of your team's culture. But that's not proof that it's athletically important.