I can't agree. We can have eternal dictatorship now. Nothing prevents it except other people, therefore people will prevent eternal dictatorship just as now (with various results).
That happened indeed and I don't think it was pretty. Although you get some exceptions, like maybe a few of the Antonines. (That didn't end well with Commodus.)
Nah, the fact that even emperors die is a good thing. No dynasty lasts forever, because after the first few generations, assets get diluted, someone spends the money, descendants fight, etc. An aristocracy that lives forever would be very hard to remove because those factors would be greatly mitigated.
