Is it? We got a big thread over in Ssd data retention - the vibe I got that it’s (surprisingly) not that bad.
Regular backups would make it periodically powered. I’ve not lost any data despite leaving flash unpowered for years.
But like any computer part, you have to plan for any single thing randomly dying.
I think the odds of everything being fine are acceptable enough for me if I check my backup integrity each time I do a regular backup. I would need to both lose my primary copy at the same time the backup copy dies, which is suitably unlikely for my needs.
(For really want to keep a long time I’ll keep multiple copies one of which on mdisc, but this is becoming increasing archaic looking).