There are companies that still use relatively old programming languages like COBOL. PL/1, FORTRAN. There are different reasons for this.
Thee are modern development tools that simplify work with these languages, for instance such tools can generate Java code that is needed to integrate a Java application with a particular COBOL application. There are also transaction managers that allow to use COBOL and Java functionality within a single transaction.
Means, old programming languages are not necessarily a hobby.
Particular programming languages or platforms are chosen usually not because of security aspects. For choice of the platform can be important the ease of development, flexibility, extensibility, possibility to reuse the code, maintainability, costs of development. Security aspects can also be important, but this is not a single and often not a major factor.