COBOL is a big example of this. It's still ubiquitous in many industries where reliability is near the top of priorities. And I imagine in 50 years we'll still

COBOL is a big example of this. It's still ubiquitous in many industries where reliability is near the top of priorities. And I imagine in 50 years we'll still very likely still have many critical systems operating on COBOL. I wonder how many will be running 'The Next Big Thing' language/api then...?