People who've been in jobs for a while have habits. They think they know the company. You being there with fresh ways of looking at things bring out these comments from them. But that doesn't mean they're committed to the old ways. Ask them for details of what needs to change to implement a new idea. Communicate with them as you get buy-in from mgmt. Usually things are the way they are for reasons, and changing things without dislodging the reasons doesn't work. Instead, start changing things from the way things are. It often works, if you don't get stopped by the comments comments. And sell them on the benefits and the vision of how things'll be with the new ideas implemented. And treat as gold their insights into what might oppose the fresh ideas- it's not them, just the old ways of thinking.