That 15km slowboat from warp in to gate on autopilot allows for a wealth of time for a pirate to target, scan, and gank - a frigate is pretty easy to take out unless it's actively speed tanking and even then there are webbers

If he'd been manually piloting he'd have warped in directly to the gate and jumped immediately - no time for an opportunistic pirate to scan and blam

There courier contracts and freight haulage corps (search for Red Frog) that will transport expensive/bulky cargo for a fee and gaurantee delivery/reimbursement