In my experience, subsidiary companies are created for all sorts of reasons (separation of IP, ownership structures, tax or duty optimisation, different employment conditions and possibly separation of liabilities)...
These reasons often become less important with time and then separate companies just come a cost burden with extra admin, tax and regulatory returns - I suspect as part of the overall ownership change for MMC, the special 3 wheeler company was absorbed/wound up as part of a typical clean up. In reality separation of ultimate legal liability is tough unless there is a real difference in ownership structure and management.
In summary, nothing sinister - likely an admin clean up.
