When it comes to refrigeration in particular newer appliances tend to break more frequently because they are using more environmentally friendly refrigerants. Old CFCs cooled really well with minimal work from the compressor. Newer fridges and freezers are more frequently using isobutane (R600a) because it doesn’t deplete ozone and it’s GWP (global warming potential) is 3 where the GWP of even non ozone depleting HFCs can frequently be in the thousands. The problem is isobutane requires higher head pressures to work properly and doesn’t cool as well as older refrigerants so the compressors have to work much harder to get the same result.

Also when it comes to household fridges and freezers, they really aren’t worth it to fix anymore. You need an EPA 608 cert to even touch refrigerants (in the US anyways). Plus you need a two stage vacuum pump and a recovery machine (amongst other things) both of which can easily cost as much as a new fridge. Then you need to actually have the skillset to remove the broken component and braze a new one in because everything uses brazed connections now to minimize leaks. Then you need to have the know how to properly recharge the system with refrigerant which when you’re working with a critical charge of maybe 2oz of refrigerant is an absoulte pain. All in all, maybe if you are already an HVAC tech and had the tools and materials on hand you might barely break even fixing your own fridge or freezer.

When it comes to consumer refrigeration they can’t be user repairable due to having to work with refrigerants and economies of scale mean they just generally aren’t worth a trained techs time to fix.