I have actually thought about this too and thought Oro should have/could have done it. but what i thought was that he either didn't actually know about the loophole which allows one to break the contract and live eternally, or perhaps it's because he wouldn't be able to gather all the jutsu in the world because he wouldn't be body-hopping. and if he continued to body hop, it would negate the whole purpose of being revived via edo tensei because the bodies he jumps to will not be immortal. when he takes over a body, it means leaving the previous body behind. and to get Kekkei Genkai techs he has to actually take over the KG body so he'd be leaving behind the immortal body--but since his soul is technically immortal anyways because he can live on in other bodies, there's really no point in acquiring one single immortal body.
that may have been confusing so i'll try and re-state it.
1. He'd be immortal anyways through body jumping, so there's no need for Edo Tensei
2. His ambition is to acquire every jutsu ever possible, but to get Kekkei Genkai techs he needs to take over the Kekkei Genkai body, leaving his previous body behind, meaning there's no point in having 1 single immortal body when he'll be constantly changing bodies anyways to gather up all the techs while also living on forever
3. Edo Tensei bodies can be stopped by sealing them, and sealing super powerful guys is much easier than straight up defeating them in a fight to the death. And, if he was sealed, he'd still be "alive" but sealed away for eternity and can you imagine how terrible that'd be? even Oro couldn't withstand the mental mind f*** of eternal immobility and isolation. So ironically Oro has a much better chance surviving by having to fight to the death and people having to kill him to get rid of him.
BUT, having said all that, unless he knows another way to come back to life, i would think he would have a very, very trusted underling learn ET just in case Oro dies and his underling could bring him back to life. He would still end up leaving behind the immortal body, but the point would be that he was alive again.
THEN again, it would be unwise for Oro to teach ET to anyone no matter how much he trusts them, because with that tech they could scheme on him and destroy him. After all, if you just give a guy hella power, you can't expect him to just not use it. especially the types of people who would work for Oro--they're backstabbers, every one of them
SO there are many things to think about and many pros and cons to sift through so it really isn't as simple as "oh i think i'll teach it to Kabuto, kill myself, and have him bring me back" there's much more to it than that.
ON the other hand, if sasuke/sharingan is his final goal body-wise, maybe he would wait til he had Sasuke's body and the sharingan, then he'd kill himself and have his underling bring him back so he'd have Sasuke's immortal body. Who knows, maybe that's what he was planning from the beginning?
so yeah, my whole point is that it's not so simple