That was an allusion to this question, which you still haven't answered. If, in principle, you could indeed decide that successful revival is possible, based only on theoretical knowledge, before any successful revival was ever performed, then you should be able to explain what kind of indirect evidence it would take to persuade you that successful revival is sufficiently likely for you to decide to sign up for cryonics.
My girlfriend/SO's grandfather died last night, running on a treadmill when his heart gave out.
He wasn't signed up for cryonics, of course. She tried to convince him, and I tried myself a little the one time I met her grandparents.
"This didn't have to happen. Fucking religion."
That's what my girlfriend said.
I asked her if I could share that with you, and she said yes.
Just so that we're clear that all the wonderful emotional benefits of self-delusion come with a price, and the price isn't just to you.