I read an article about business which had this classification, "Would be weird if it worked", "Might work", and "Would be weird if it didn't work" and argued that you want to be in the last category.

In engineering we aspire to a slightly stronger standard: "I made it physically impossible to fuck this up."

You've completely missed my point. I don't even accept the premise of the JWT standard. But the eventual migration to safer default settings, in a format that continues to expend implementation effort to support settings nobody should use, is in fact a practical engineering problem with the standard.