I feel that at the very least, the customer in that case should be entitled to a complete refund of the product, regardless of whether they bought it 5 days or 5 years ago and regardless of the condition their device is in.

This should at least give some incentive to companies to not perform such sweeping changes to their terms of service and if they do, the customer can more easily remove themselves from the lock-in without taking a financial hit.

Convenience for end-users and avoiding link rot is probably one of the reasons.

yeah, tunneling into your local network and then calling WoL from there is the way to go.

Not selfhosted but I think Pocket also falls into that category of service.

While Vaultwarden is great I would not suggest selfhosting your password manager unless you do regular backups. Losing all your password cause your server went down is a great way to ruin your day.