Machines already design and build other machines, machines already troubleshoot themselves, and machines can repair each other and install themselves easily.
Before you think you can’t be replaced look at the modern age of mining. Strip mines run with dozens of machines that don’t have any people in them, there’s one person in a tower watching and not pushing the kill switch.
Not being in the industry you don’t have the slightest idea of what you are talking about.
Putting aside the necessity of cognitive reason in some tasks (the LOUD dirty cutting of the stone must be accomplished AROUND funerals and visitors) Any ONE of the separate tasks can be done by a machine and the main task already is (actual blasting of the stone albeit in factories)but once you try to put ALL of the tasks to one machine you have an impossibly complicated and huge machine and even then it CAN’T EVER BLAST AS FAST AS A MAN thus making impossible any hope of even getting past five jobs a day.
Very few cemeteries would allow a machine of any size to drive over the graves since the weight of even an F350 superduty with compressor will collapse the graves and eventually get stuck.
It will happen that people will be to poor to provide for tombstones before I will be automated out of a job.