Here’s a copy paste from superuser that will hopefully show you that what you said is incorrect in a way i find expresses my thoughts exactly
Magnetic Field Breakdown
Most sources state that permanent magnets lose their magnetic field strength at a rate of 1% per year. Assuming this is valid, after ~69 years, we can assume that half of the sectors in a hard drive would be corrupted (since they all lost half of their strength by this time). Obviously, this is quite a long time, but this risk is easily mitigated - simply re-write the data to the drive. How frequently you need to do this depends on the following two issues (I also go over this in my conclusion).
You’re wrong. HDD need about as much frequently powering up as SSD, because the magnetization gets weaker.
Here’s a copy paste from superuser that will hopefully show you that what you said is incorrect in a way i find expresses my thoughts exactly
https://superuser.com/questions/284427/how-much-time-until-an-unused-hard-drive-loses-its-data