[thisgoodlife]

If I were the customer, I’d reject your proposal too. The old software has been working fine for 40 years, why would I want to find someone to rewrite it?

[jandrese]

In this case it would be to prepare for the inevitable death of the last machine in the office that can actually run it.

[icedchai]

With emulation, it can run forever.

[bombcar]

The death of the user is more likely than the death of the ability to run the spreadsheet; updating can wait until that time if necessary.