Luca had always known that he would never be able to take out his father if he didn't have the support of many behind him.
Since a lot of people within the company didn't like what Vince had done to the Falcone reputation, many were on Luca's side and he had meticulously planned meetings with various people who could support him in the future if things ended up taking a turn for the worse.
However, his dealings never went just one way. He also had to keep meeting with some of his father's men to continue establishing himself as an obedient son even if he didn't always do exactly as his father wanted.
The older, traditional men in the mob simply thought Luca was rebellious because of the money he was raised around. They didn't care about his antics as long as he never got in their way. This gave Luca a longer leash. It gave his father the impression that Luca wasn't planning anything on his own.