There is a very lucrative 'niche' industry that's grown up around supporting the aging computer infrastructure. Most companies can't keep dedicated people who know and understand the older programing systems/languages (Fortran anyone?), and the big chip manufacturers can't be bothered to maintain production of decades old component designs. OTOH, it was cost huge money to replace the hardware and software of large computer systems that date back to the 20th century. So these companies provide contract support services to maintain both the hardware and software of those older systems - and can charge handsomely for it.