The Walkman and other tape players were so much superior to CD players for portability and convenience. Batteries lasted a lot longer for portable tape players than for CD players. Tapes could be remixed easily so you could bring a specific playlist (or 2 or 3) with you. Tapes were much more resilient than CDs. The superior audio quality of CDs didn’t matter as much when you were using 1980’s era headphones. Or, even if you were using a boombox, the spinning of a disc was still susceptible to bumps or movement causing skips, and the higher speed motor and more complex audio processing drained batteries much faster. And back then, rechargeable batteries weren’t really a thing, so people were just burning through regular single use alkaline batteries.
It wasn’t until the 90’s that decent skip protection, a few generations of miniaturization and improved battery life, and improved headphones made portable CDs competitive with portable tapes.
At the same time, cars started to get CD players, but a typical person doesn’t buy a new car every year, so it took a few years for the overall number of cars to start having a decent number of CD players.
But what is being repaired? A machine of some kind? And the machine is operated in pursuit of another actual productive activity, right?
Machines are just about the application of mechanical force in some way, and that in itself isn’t an end goal. Instead, we want that machine to move stuff from one place to another, to separate things that are apart or smush/mix separate things together, to apply heat or cooling to stuff, to transmit radiation or light in particular patterns.
Everything in the economy is just enabling other parts of the economy (including the informal parts of the economy). Physical movement of objects isn’t special, compared to anything else: kicking a ball on TV, singing into a microphone, authorizing a wire transfer, entering a purchase order, answering a phone, etc.
I’m not seeing a real distinction between an IT consulting business and a heavy equipment maintenance/repair business. The business itself is there to provide services to other businesses.