As for the service, it doesn’t look very expensive to run, 1 or 2 new clients a year is probably enough to sustain it. I would expect it to run so long as the owner is alive, ironically.

I doubt blockchain will be permanent either. At least it’s distributed I guess which is less fragile than a website. Maybe it would be better if somebody just embedded a (very small) obituary and picture into an RFID or something and epoxied it into the granite.