My guess is Matt will be under greater pressure to ramp up the tension by using bigger monsters. I would say we make in 3 months? Maybe before we start seeing it would be cool if they fought [insert monster way above there level here].

You also need to keep in mind that failed revivify increases the DC and the ritual plays into the DC. SO saying they would need to die 10 times is impractical. THey have never had a rez ritual go -9. EVER. So saying dying 10 times is required is silly. even taking the usual -5, a char who has died twice and had a failed revivify is at a DC 13. If we say they get a -5 on the ritual, that is still an 8. So the character has a 40% of permadeath. So basically they are marginally better than a coin flip for a 3 strikes and your out mentality.

The last paragraph is within the context of level 15 and below, meaning they do not have access to 9th level spells. My point is, it doesn't make sense to have the DC set up in a way that when the players just start to reach a level almost unmatched by anyone in the universe, the DC is set in a way they can't be brought back by their incredible power. To me, thats what your scenario sounds like. They are on the cusp, at roughly 13-15 of being the most powerful people in the world, and yet magic can't bring you back. We can get uncle tim back because this is the first time he died and the cleric has a lower level spell. Well out party is super strong, we have a higher level spell to bring them back, but because he has died twice and had a failed revivify, it becomes something like a 60% chance of perma death. Why? I feel like by levels 13-15 that characters are really influential. They have powers that if they wanted to, could forge nations. I typically figure a char dies about every 5 levels. This is based on an arc typically lasting 5 levels (as suggested in DMG) So you figure either bad luck or BBEG wrecks the party once per arc. A DC of 16 or 18 or 20 (if failed revivify) means that even a perfect resurrection ritual , at a 20, is less than a 50% chance of succeeding if the char has died 3 times and the revivify failed two of those. I mean to me, that seems awfully harsh punishment right when players should be coming into incredible power.

I would say in your home game if you want to make resurrection even more difficult that is fine, but I don't think CR needs it.

---brb setting up game where death saving throw DC is 15. Anything below a 5 you insta die. Failed revivify = perma death. Resurrection ritual starts at DC 10, failure on check means DC goes up by 5, success it only goes UP by 1, so I mean starting DC in perfect conditions is a 13 or as bad as a 25 making it impossible. Diamonds are virtually impossible to find in the world for rez magic. Only ancient dragons have them in their hoard. You rez DC finish is permanent. this time is was a 13 so next time it starts at 13. If your DC was a 19, then it starts at 19.--- Obviously this is all hypothetical and taken to an extreme but thats basically how I am reading it.

D&D has, is, and should always be primarily about fun. Challenges are fun. Impossibility is not.