Indeed repairability may have been the biggest change. Major appliances centralize virtually all functions including on one or two main circuit boards including the high-voltage relays which in my experience are very prone to failure (they used to be mounted separately in a different location on older appliances). Those circuit boards typically cost ~1/3 the cost of a new appliance assuming you source and swap it yourself.

In conjunction with the decline of repairability in the appliances I think there's a corresponding decline in repair skills among the general population as well.