I work in a place where we have (former) COBOL developers and the actual mainframe. One co-worker worked here for 25 years until they retired last year (does it sounds like trade union propaganda already?). We also have a lot of 20 years old for whom it may be the first job.

Somehow it's consistently no drama and no nonsense place. Compared to the frat house atmosphere of the usual tech startup, it's really different.