If a large number of people get reanimated, I don't think this will be their fate.

I can imagine "educators" who can get them up speed. In a future where people get reanimated, I would think this shouldn't be a problem long term.

Any existence may be better than non existence.

Retraining people once they're alive again not only requires logisitics and hiring N-centuries from now, but also requires that anyone really cares. You could imagine a world where 100s of people are being reanimated at once, but I don't think the economics would ever let that event happen.

Once this passes through a few generations of people responsible for tending to the needs of rich people's frozen brains, the empathy and money will be gone. Imagine inheriting a business funded from people wanting to skip over the entirety of your lifetime because they assume your time is too boring for them. Plus, your impact on that business will be null. There is nothing you can do except keep it going and get more rich people's brains in there. The only "innovation" that's going to drive business is bringing someone back to life... which for a large span of brain custodians, will only be possible AFTER their death. Maybe you need to model it after a religion; humanity has kept stuff going for long spans of time under that framing... but are you still just a servant to these ancient people who you have not met, and will actually NEVER meet since you'll die first... having spent precious time in your life taking care of them? Seems like an uninspiring religion.

Or... you do some fraud, which is much easier. They're already functionally dead, and you presumably have access to a lot of their money. Money that is worth more in your lifetime, than in their future.

People have historically cared very little about the personal feelings of the pharoah as they dust off his bones and take his nice things. Doesn't even need that long. Guess what, T+200 years, the brains are getting dumped in a river.