It's possible, just slower. Also, if you start in 1081 when the Empire is small you have an easier walk to the throne since you have less opposition.
Don't expect to become emperor in one lifetime though.
I’ve gone at it three different ways: lower the Crown Authority to limited, then annex your fellow vassals until you can usurp the Empire; expand through holy wars until you become king of Armenia, then forge a claim to the Empire; or marry a princess, press her claim, and wait for your children to inherit. (Although when I did the last, Empress Zoë Doukaina took up celibacy and gained the nickname, “the Fat.” In her defense, I’d by then legitimized two natural daughters.)