Most failures I've seen are either mechanical wear on a port, button or cable of some sort, glass panel damage or a power supply system not being built fully to spec because of cost cutting or stupidity. Also batteries wearing out due to use or more rarely, ssd storage drives wearing out due to usage. There is also 'glue & waterproofing wear' as the glue & rubber goes through multiple heat / cooling cycles and unsets, then water damage occurs.

Those issues will never be going away on some level. The chips themselves are usually the most reliable components, unless they are power management chips.