You're not wrong, but equally I'd argue that if you need a huge amount of groundwork to implement change, you're probably in the wrong organization.
Good organizations value good ideas, irrespective of who thought of them.
That said, my experience tells me there's a lot more to it in some cases, org dependent.
For example - all teams (even great ones) go through phases where they can tolerate more change than at other times. Why that's true is itself a huge list of factors ranging from what the org is doing as a whole, all the way down to the team itself and how they're currently working.
It also matters how the idea is spread among a group. If the idea has legs, theres going to be a lot of broken telephone if you haven't correctly setup the context with thought leaders (which may be different people to the managers, who also need to know what's coming). This gets more challenging as the number of people involved gets larger.
Ideas with only upside and no downsides may be trivially executed. The problems come with ideas where costs are certain and up-front, while benefits are medium-to-long term, and the transition may carry risks of its own. Big changes and ideas usually are disruptive and the best organizations may still struggle to pull them off.
In my experience even in good organizations people may have different assessment of what's a good idea precisely for these reasons, and getting people aligned behind such changes is what leadership is all about, and does need patient groundwork.