I would answer to this that the mathematicians (humans) are the ones who give any meaning to mathematical discoveries. If we don't have mathematicians anymore, the result is that AI can find whatever they want, but 99% of that will be useless waste. Outside of practical applications, the only reason most mathematical results have any interest is that lots of mathematicians spend time trying to find their solution. Once humans stop caring, mathematics done in an automated fashion will also stop having any value, other than its possible use in finding solutions to existing engineering problems.