Because their focus changed from "outright, manu military conquest" (Remember what Bane said about Khan "Deploying air forces… flanking armies… you are thinking like a dirt general, not a Sith") to inflitration, subterfuge, corruption.
>your numbers when your goal is to overthrow the massive and supremely powerful police force of the galaxy.
They tamed, or so believed, the Dark Side. With the Force under their control, they believed they could do anything. "The hability to destroy a planet is insignificant, next to the power of the Force"
>>7516
>as he never had an intention to take on a "worthy" apprentice, deigning only to take on lesser servants like Maul and Vader.
Nope. Darth Vader, pre-Mustafar, was his wet dream, the one who made him wet his panties. And even sometime after Vader was put into the suit Sidious thought that he could reawaken his power.
"Fundamental to Vader's growth was the desire to overthrow his Master. Had Vader killed Obi-Wan on Mustafar, he might gave attempted to kill Sidious, as well. In fact, Sidious would have been surprised if Anakin hadn't made an attempt. Now, however, incapable of so much as breathing on his own, Vader could not rise to the challenge, and Sidious understood that he would need to do everything in his power to shake Vader out of his despair, and reawaken the incredible power within him. Even at Sidious's own peril…"