I would advise against specializing in any proprietary language or ecosystem. You might find it lucrative, but the long term damage to your career just can't be

I would advise against specializing in any proprietary language or ecosystem. You might find it lucrative, but the long term damage to your career just can't be compensated for. Also, don't believe them if/when they tell you they are looking to migrate to something more reasonable as part of their attempt to get you to join. I interviewed at a place that did VB6, but they promised work in .NET during an upgrade, but I suddenly found myself reading COBOL and being asked how excited I would be learning JCL. They are still on VB6 and I left there only 8 years ago.