Do you think the days of the hard drive is finally over?

So Seagate and other makers are getting ready to introduce 20 TB HDD's
to the market. According to Seagate, its fastest drives are capable of
sustained 250 MB/s transfers (if you believe them). It would take 30+
hours to entirely fill such a drive with data at maximum speed! Is that
too much time, no matter how much capacity you are getting? Is that
basically unusable capacity? I know you can say that a drive that large
would be filled over a number of years, and no one would be filling it
all up in one go.

But that's probably true in a home environment, but what about an
enterprise environment? What if that drive were part of a RAID array,
and one of those drives failed and needed to be replaced? In RAID
parity, the entire drive has to be written to, because the parity is
required on all drives at once. Imagine you start synchronizing a
replacement drive like that, and it takes 30 hours to do that? That's a
long enough time that it's conceivable another drive within that array
would fail too, before it's had a chance to completely resync with the
array. So sure, you can get that capacity with an HDD, but should you
really be storing your data on something that slow? HDD's can't get much
faster.