You can’t really cheat your way to a better presentation. If the “spitballed” version is good enough for the situation, why expend a lot of effort on preparation?

Maybe the problem is that people have low expectations when everyone delivers bad presentations. This kind of cultural thing is often easier to fix by changing the format rather than pushing for everyone to do more — in other words, ask “do we need all these presentations?” instead of “why do you all put so little effort in your presentations.”