Just the general, pervasive use of lesser quality materials in just about anything made these days. Plastic cases instead of metal are more prone to incidental damage. Plastic knobs, soft buttons, materials that trade longevity for Eco-friendliness, planned obsolescence, etc.
Combine that with the disposable nature of society these days, people are more apt to toss something than fix it, so more stuff will head to the landfill more quickly than in the past.