It depends on the speed of change though. If a million-strong industry collapses overnight, it can lead to really painful social disturbances. If it winds down in 10 years, the transition can be much more smooth.
BTW see also https://www.edge.org/conversation/gin-television-and-cogniti...
This is an intentional policy choice btw. You could just legislate the horseshoe company pays 90% of each displaced blacksmith decreasing by 5% per year.
At the start of the last century the UK had a million people working in the coal mining industry. Now it is effectively zero.
That reduction happened over a long period but it wasn't without its problems. Even now there are old coal mining villages that have never really recovered economically.