[Karunamon]

Often the "why they're still in use today" when describing legacy tech can be described as a combination of fear of change, lack of resources, and technical debt (the result of both of those things).

Not because it was or is the best tool, not because it's the most efficient or the most performant or most readable, but because simple mundane politics and FUD.

[jeremiep]

There's also the cost of upgrading a code base to a more modern language vs the benefits of working in the new language.

Most legacy projects I've worked with were not that hard and costly to maintain. Rewriting these code bases would definitely cost more than what would be saved afterwards.