Organizational cultures are infamously hard to change. Jeff Bezos made the point that your culture is set after your first 100 hires, because after that, the mass of the existing culture is too much for any newcomer to change it effectively. This has both good and bad aspects - once you've found a successful culture, changing it can be detrimental. You have to be very certain that you're making positive changes. And of course, the hardest kind of cultural change is when you've found a local maxima - then you have to make negative changes to get to a new high, and that's really hard - it's hard enough to get a large group of people moving in one direction when the goal is obviously better. When it's a leap of faith that will be worse for a while - much harder!
It's very natural also for organizations to be filled with people who have "selected into" the culture. That's the point of the Bezos idea above - once the group gets big enough, it's very hard to be in dissonance with the overall culture. So there tends to be a lot of reinforcement.
In that context, challenging ideas are received in one of two ways: either rejection for some fundamental reasons that are inarguable ("that can't be done") or rewritten into the "rules" of the culture and neutralized ("we are already doing that, shhh"). To some degree, these two poles are always "right"- there are always challenges and problems with any new idea (so "that can't be done") and in a large enough organization, there are always projects or at least large groups where any new thing might fit, or principles that cover it, particularly if the manager has done their job well ("we are already doing that").
It's challenging to react to new ideas in a different way, but it's helpful to be aware of the pressures towards the status quo. One way to break out of this mentality is the "yes, and" mindset. This is something used in brainstorming and improv - the only rule is you can't reject the idea, you have to say yes, ",and" add something to it. So, for something that seems uncomfortable and impossible, we try to look at ways it might be approachable, or things that may have changed that make it more achievable. For the other side of the coin, we have to look honestly at how the new ideas would fit into the existing work and budget - it's not enough to say we "could" do something, we have to be able to firmly say we are doing it, and that involves deeper thinking about what does and doesn't match.
This is all challenging. Large groups always have full budgets and well-defined agendas. New ideas are mostly a distraction, and usually aren't useful. But it's not healthy for any culture to stop listening and incorporating new ideas, and if it's very challenging to change, it's worth thinking whether the culture has found a local maximum that isn't really optimal.