Hard drive makers have been able to make 1 TB platters for a while, so 5 TB drives wouldn't be a problem at all (or even bigger drives, though in the past few y

Hard drive makers have been able to make 1 TB platters for a while, so 5 TB drives wouldn't be a problem at all (or even bigger drives, though in the past few years 5 platters have been the maximum). They simply chose not to make them because the demand even for 4 TB drives isn't so strong.