[jimmygrapes]

Perhaps a simple solution is worth a try: publicly praise/acknowledge those who excel, while also teaching that it's okay to not be at that level [yet]. Encourage peer mentorship, so that the more advanced ones can help someone who struggles. For the outliers who are absolutely stuck in the "I don't care" mindset, apply additional resources to find alternate ways to make the material matter to that individual (practical examples, scenarios, hands-on application, etc.). Ask other students who are interested what real world uses they can think of for the material/topic/equation/concept. If something works, consider implementing that method for the entire class earlier on for the next class.

This is where the goalposts generally get shifted toward teacher resources and/or pay. That's fine to discuss as well, but likely not a significant factor for the above suggestions.