> Hiring a janitor or cleaning or supervisors etc was so much cheaper than it is now due to Baumol's.
IIUC, this is an inappropriate of use of Baumol's cost disease. That is intended to apply in cases where the fundamental issue is that technology and/or process changes cannot improve the productivity of those performing a task, such as a symphony orchestra. Janitorial work has been subject to productivity increases, and ultimately, it's a bit of a stretch to use Baumol's to talk about a case where you can't for some reason reduce the number of people doing the work from one to zero.
Supervisory roles might, possibly, be an appropriate Baumol's example.
By that criteria, Baumol's doesn't even apply to symphony orchestras. Technology has made symphony orchestras marginally more productive. Instruments are better and more consistent, recording technology improves practices, et cetera.
Baumol's applies to anything where technology has improved the field significantly less than average. That includes both symphony orchestras and janitorial services.
If the function of a symphony orchestra is to perform symphonies, there has been essentially zero change in their productivity for several hundred years. Contemporary instruments are no better than they were in the mid-1800s. Their rehearsals are rarely recorded, and even if they were, it is much less common for this to contribute to future rehearsals.
Wikipedia says that Baumol's is:
> the tendency for wages in jobs that have experienced little or no increase in labor productivity to rise in response to rising wages in other jobs that did experience high productivity growth.
while it's not the canonical source for the definition, it is notably more specific than your version.
IIUC, this is an inappropriate of use of Baumol's cost disease. That is intended to apply in cases where the fundamental issue is that technology and/or process changes cannot improve the productivity of those performing a task, such as a symphony orchestra. Janitorial work has been subject to productivity increases, and ultimately, it's a bit of a stretch to use Baumol's to talk about a case where you can't for some reason reduce the number of people doing the work from one to zero.
Supervisory roles might, possibly, be an appropriate Baumol's example.