This might depend on how long it takes to develop revival. Any estimates?

If it's just a few decades, cryonics companies might want to signal trustworthiness by reviving everyone.

In The First Immortal, a science fiction novel about cryonics, there's a law that no one gets revived unless there's someone willing to do the work of integrating them into the future society.

In other words, you'd do well to be an interesting person, and better to be from a family with a very strong culture of loyalty, though I suppose that integration could also be a matter of contract with a cryonics company.

why should the future want us?

Someone who knew you may want to bring you back.
If it takes centuries, then the more people frozen the better since it will be more likely that someone you knew would be brought back by someone else. And then he may bring you back too.
This assumes that the government does not prevent people form doing this.

Conclusion - to me it seems that if you want to maximize chance of future society resurrecting you, keep cryonics as close guarded secret of tiny elite...

I hear this from cryo skeptics all the time. Doubts -- not so much as to whether it works or not, but as to whether the patients who could be revived are human or not. Your whole argument treats the patients as dead and gone, and the people who would die without cryonics as expendable. It is simply not consistent with cryonics working in the first place.

If cryonics works in the first place, it means everyone who could be preserved but isn't, is a human casualty -- and everyone who could be reanimated but isn't is stuck in a coma against their will. I don't care if you give that an arbitrarily low probability, but if you are going to argue about what is the case if it does work, you have to remain consistent with that assumption if you want to criticize it effectively.

Luckily, future humans will have experience with suspended animation and radical surgery long before they can realistically revive a cryonics patient. Getting someone suspended with near-zero damage is an unsolved challenge, but few seem doubtful that it will be solved at some point. Repairing the damage of a current-day cryonics case is necessarily further down the road.

Simply having experience with reanimating suspendees (and seeing major surgery such as full body replacement using regrown organs), I expect they will have a much more enlightened perspective on this situation than your average cryonics critic today. Death will then be viewed as something extremely uncommon and in need of extremely good evidence before medical procedures and ethics can be cast aside.