Cost of manufacture has steadily dropped while cost to repair has stay the same or increased. Manufacturing is designed for assembly, not for repair. There is no economic pressure to have appliance manufacturers design and produce appliances that can be easily repaired.
Effects of Mass Manufacturing
Mass manufacturing has gotten very efficient at producing complex pieces of equipment quickly efficiently and on a razor thin margin. Designing a piece of equipment to be repairable costs extra design time. It also raises the cost of the appliance at market. When a product is being sold on thin margins, adding cost to a product that doesn’t give the customer any kind of benefit is a cost add that won’t help sales. Unless there is government pressure and regulation to require appliance manufacturers provide certain base levels of repair-ability, it isn’t going to happen.
Plus complaining about the controls in a system like that isn’t going to get any traction here. Appliances have energy standards they have to hit. You often need controls to do all of that.
Reliability of the parts in appliances is very high now. So it isn’t like you need to have a repairman in every couple of months to repair an appliance. Appliance normally operate for several years before something breaks.
Labor Costs to Repair an Appliance
In addition, the labor cost to repair an appliance is exceedingly high. If repair technician wants to get paid (in his pocket) $25/hour, they end up having to charge $35-$50/hour. Diagnosing an appliance is going to take an hour or more. Plus there may be a minimum diagnosis time that covers driving to your home. PLUS repairing it is going to take an hour or more, plus the price of the parts.
For a six hundred dollar refrigerator, I’ve just spent at least a $100 dollars in labor plus the price of the parts to repair it. Parts is easily going to cost another couple hundred dollars. So for a basic repair, I have just spend half the cost of buying a new unit. If you have to replace the compressor, you are paying for at least four hours labor, plus a refrigerant charge. This cost is to drain the refrigerant from the system, and then to recharge after the new compressor has been installed. So the cost to replace a compressor is going to be $550. 50 diagnosis + 200 repair + 100 refrigerant charge + 200 compressor. At that cost, I could have just bought a new fridge.
Getting Parts to Repair an Appliance
This says nothing of having to actually get parts to repair an appliance. If the repair technician has to have parts shipped in, that is going to cost extra. Overnight shipping charges for parts is based on weight; so if I have to bring in a light part, that is going to cost another $50 in shipping. If I have to bring in a compressor or other heavy part, the cost of shipping is going to be several hundred dollars (and that makes it cheaper to buy a new appliance). Sure the cost of shipping goes way down if you are willing to have your appliance fixed next week.
And to answer you question: Why doesn’t the repair technician keep those parts on the shelf to repair an appliance? Those parts are expensive and parts don’t pay the rent. So if the technician buys the part and it sits on the shelf for six months, that is money tied up in something they can’t use. So they don’t buy parts they don’t need. The local warehouse might have those parts available, but its a crap shoot, and they won’t have specialty parts sitting on the shelf. Parts for appliances change every couple of years and if you end up with parts on the shelf for a unit that isn’t sold anymore, good chance you have spent money on parts that you will never sell and you have to take a loss on those parts.
Should You Ever Repair an Appliance
Yes, you can purchase appliances that are repairable. These are generally commercial and industrial grade (and sometimes ultra high end residential that is normally rebadged commercial). The purchasers of those appliances expect to use those appliances for for longer than residential units (and run them harder as well). So repair-ability is actually considered. You can also see the price of those appliances is significantly different (the starting price is about double of residential).