For several really good reasons, the main one being that this type of equipment is often almost worthless after just a few years.
If you then add in poor serviceability and poor audio performance, compared to even modest hi-fi stereo gear, you end up with very few reasons to repair this stuff.
I always ask one critical question about equipment being considered for repair:
“Is repair economically viable?”
Even some of the cheapest hi-fi gear from the ’70s is still sought after for its performance, reliability and serviceability. The same unfortunately cannot be said for the plethora of average sounding, cheaply-made and forgettable home cinema equipment from the last 30 years or so.
Most of it is worth almost nothing after just a few years, due to useless feature creep. This kills retained value and therefore repair viability. Almost all of the cheaper stuff and much of the better stuff is only marginally serviceable, because:
- Much of it is so cheap or now worth so little that it’s barely worth opening, let alone repairing
- Critical parts are often no longer available and SMD chip-based boards like HDMI controllers are not designed to be repaired, so whole boards are often needed
- Repairs can easily exceed the value of even more expensive AV gear, again killing viability.
There are some notable exceptions, but sadly though, home cinema gear is just desirable in the way hi-fi stereo gear is.