Charters are sky-high - up to $200,000 a day for a container ship. And then you may well sit offshore for days/weeks waiting to unload at dock. We need more docks.
So when you say a charter is $200,000 a day, if I pay $1.5 million to buy a container ship, I can possibly "rent" (charter) it for like $200k a day? Even $100k or $50k a day would be killer. But that doesn't make a lot of sense... everyone would be buying container ships...