In the beginning, all electronics devices had schematics and tube placement diagrams glued to the bottom or inside cover. Tube circuits were relatively easy to repair. Repairing tiny circuit boards with surface mount components is a different matter. Given the cost of repairing today's electronics in comparison to the cost of a replacement, there is no decision to be made.
That being said, having to pay $1200 to $2200 for an animated temperature controller is outrageous. My next furnace will indeed have a simple on/off thermostat.
...and so on.
I haven't had to do repairs on modern electronics boards in recent years. The use of SMD and reflow techniques requires tools I never needed in the past. My vision is no longer razor sharp. My hands are no longer steady enough for neurosurgery. Age takes a toll. Retirement approaches. The cost differential between DIY and hiring help may influence my choice to retool or not.