Jummah sermons

What's the thought behind jummah sermons as majority of time imam is only discussing the personalities and they don't relate how Islamic teachings can be implemented in modern world or how the modern problems can be tackled. I've never heard anything about waste of water resources or time or how we can improve the society instead I only hear about the contributions and importance of Islamic personalities which no doubt are great and they have done great work for the religion but I think they did it to serve Islam and wanted to educate more people about that and now we instead of educating people about religion more focused about the personalities only why is that so? How we can improve the youth's connection with mosques although I strongly believe that every mosque should include youth in their management but it's a long shot and I want to know more about your thoughts on this how to improve this situation.