obito barely considered itachi a blimp on his radar. his only concern was getting the jins. when itachi died, did obito rush off to kill him some konoha ninjas? NO. whatever personal revenge he wanted to do to kakashi had to wait. the priority is the jins.
and they tried to get naruto when he wasnt in the village like with deidara and kakuzu. its not like kakuzu is gonna be like "oh wait, its naruto. off limits guys, off limits".
and hidan is definitely going to ignore obitos orders.
Obito left Konoha alone until AFTER Itachi died
and then continued to leave it alone, choosing instead to declare war on everyone.
However, there was one man he did not cross and that was Itachi.
because he doesnt want to lose himself a powerful subordinate
Obito has said on 2 Occasions that he is really relieved that Itachi was gone.
lol because he knew itachi wanted him dead. but he couldnt exactly publicly move on itachi, since that loses them the powerful subordinate they need to help seal the bijuus and further their ends
However, the only person he never eliminated was Itachi because due to Obito's belief that Itachi would kill him if he knew his secret. Obito feared him and kept his distance.
funny since i seem to remember obito laughing off itachis final assasination attempt and calling him a fail.
and for someone who kept his distance, he not only knew everything about itachi but also itachi spent enough time near him to rig a trap to react to obitos own sharingan. how could he if he barely ever even saw said sharingan in the last 10 or so years.
obito confirmed he was stronger than itachi.
he said "i kept a few secrets of my own. if i hadnt id be dead".
this means itachis only shot of killing him via surprise assasination was with full intel. he wasnt talking about face to face combat.