Why Cluster A Primary Key?

I'm probably going to get shot down with thousands of reasons for
this, but I've never really heard or read a convincing explanation, so
here goes ...

Clustered indexes are more efficient at returning large numbers of
records than non-clustered indexes. Agreed? (Assuming the NC index
doesn't cover the query, of course)

Since it's only possible to have one clustered index, why is this
almost always used for the primary key, when by definition a primary
key will always return 1 record?

Isn't it generally better to specify a non-clustered index for the
primary key, and reserve the clustered index for a column which will
most likely be used for queries that return multi-row data sets (e.g.
date columns)?

Also, if you are using a sequential key, clustering this will cause an
insert hotspot on the last page of the table, which can cause
concurrency problems if you aren't using row-level locking. If you're
using a random clustered key then inserts will generally be improved,
assuming you're using a sensible fillfactor, but you still lose the
advantage of using the clustered index for multi-record retrieval.

I'd be very interested to hear other peoples' views on this.

Phil