Denver never said he'd be the starting QB for the season. They specifically said he'd be the starting QB for training camp. You have a chance to get Manning, you dump Tebow in a heartbeat! This is solid logic for the team and management perspective. Pro sports are ALL about winning and the money that accompanies it... so it just makes sense. Most pro players know how the system works and keep their eyes on strategic moves off the field as well as on... part of the biz of being a pro.
They made the right choice with Manning!