Yes, we all have clients who can't be bothered to back up their computers - but I'd be surprised if anyone has many clients who aren't aware that they should. As long as we've provided the correct advice and set up the correct systems then really that's all we can do. We're not responsible for our clients' behaviour, or their choices, and I think it's appropriate to let them behave like adults and experience the world accordingly. Some of those choices lead to unpleasant consequences but as one of my wisest clients once observed "I've lost all my data but no kittens were hurt", and nobody seems to go through a significant data loss more than once.
We routinely replace HDDs with SSDs, both as upgrades and as repairs, and we always make sure that there's a backup strategy in place - automatic cloud backup if possible, automatic backup to an external drive if not, manual backup to an external drive for really weird cases - but there's always a backup before they take the computer away. Anything less is unprofessional, anything more is mollycoddling.