A high-pressure, do-or-die, performance pitch is not the best format for evaluating ideas. Leaders who moved up the ranks from sales roles often put too much value on the salesmanship in presenting ideas.
Another approach is asking individuals or teams to bring a rough prototype of their idea. Share their observations of the problem they’re solving, how the came up with their idea, how they tested it in some way, and the results. This may require a small amount of money to create, as well as a reasonable bit of their time. The fact that the have some investment of time will help them make diligent choices on what ideas to pursue.