The advantages of being Hillary Clinton in the presidential race just starting are these:
1) Everyone knows you to be a corrupt, manipulative deceiver who is motivated solely by your own interest, and knows you so well that absolutely nothing you can do or say will surprise anyone. No scandal can derail you, because no one expects any better from you.
2) This corruption is a positive recommendation to the richest and most influential political factors: large banks, multinational corporations, and big Labor. They will be delighted to have a President whose administration can always be bought when there's a difficulty.
3) You stand astride a Democratic National Committee that will not dare to cross you. The nomination, at least, is yours unless your health should decline so suddenly that you cannot plausibly serve as President. It is "your turn," everyone agrees, and no one who might credibly challenge you is preparing to do so.
The disadvantages are these:
A) No actual citizens want you to be President.
(i) The true Left does not believe in you.
(ii) The Right doesn't like you either.
(iii) The moderate center tends to want honest, effective government at relatively low tax rates. No one thinks you will provide any of that: the corruption of Clintonworld is infamous, the ineffectiveness of the State Department under your leadership compellingly obvious, the failure of your signature health care proposals your other most famous 'achievement,' and your readiness to raise taxes assumed.
B) Machines can get votes lined up in spite of zero enthusiasm, but that only gets you the bluest states. You've got to be competitive in states where machines such as labor unions are much weaker, such as Florida.
So you'll have plenty of money, given (2), and an easy path to the nomination, given (3). You'll thus have tons of cash to focus on the general election, and you'll be running against a Republican who will be weakened by the primary -- with any luck, some of his flaws will have been exposed for your attack dogs.
Still, you've got to get people to show up and pull the lever for you. No one really wants to. The worst part of being 'inevitable' is that your forthcoming Presidency is seen as a sort of chore even by Democrats. Maybe it's just something they have to do, but it's not something they are at all looking forward to doing.
I wouldn't be surprised if, in the end, that lack of enthusiasm is enough to prove her undoing.