Both sides of the business
I spent the beginning of my career in TV shops, then ended up on the manufacturer's side working with these same shops.
The most successful shops were diverse. One shop I worked for did TVs, stereos, VCR, CD, DVD, videodisc (all), major video games consoles, dashboard video monitors for cars (remember those?), microwave ovens and just about anything under the sun they could get warranty status for.
Sadly, most are obsolete or too inexpensive to repair. Indeed, as a manufacturer, small LCD TVs were too inexpensive to field repair and became depot repair. Large LCD TV and high-end electronics seem to be what's left in field repair. I suppose whatever is too heavy or too fragile to ship is what gets repaired in the field. Still an exception to that is cheap microwave ovens.