There are quite obviously consequences, but perhaps not for the people who are in a position to ensure the containers don't fall overboard? Somebody is certainly losing money here.
So insurance companies are losing money and raising premiums accordingly?
Perhaps nobody is losing enough money to really care about the problem. The graph in the linked article suggests that 11 out of the last 13 years, losses have amounted to around $80 million or less. A lot of money, but perhaps not a lot of money to the shipping industry and/or their insurers?
Considering there are individual ships that carry more than a billion dollars worth of cargo and way more containers in a single trip than are lost in total in a year, I think you are probably correct.