Unlike solid-state devices, most general purpose capacitors have a MTBF measured in '000s of hours (I've just looked at Maplin, and a so-called long-life electrolytic capacitor has a MTBF of 2000 hours).
Now this may seem like a long time, but with modern devices having always-on power supplies (identified by no physical switches) that contain electrolytic capacitors, then we are actually only talking 83 days being either on or on standby before you would expect a failure from this type of device. It's amazing they last so long.
When this type of capacitor was first invented, it was expected that any device would only be on for a few hours a day. But now we expect everything to come on at the touch of a remote control, everything is different.
I have talked to a Sky box specialist repairer (when my 1st gen Thompson Sky HD box failed due to capacitors in the power supply) and he said that these boxes were not expected to last more than about two years before failing. They sell hundreds of capacitor kits to repair this very fault. This explains why the after-market Sky insurance services are so prevalent.
The simple fact is that anything using cheap electrolytic capacitors must be expected to fail after a few years unless the manufacturer has made special efforts (such as using new technology solid-state capacitors). Unsurprisingly, this costs more money, and is unpopular for all but the most expensive devices.
As a sideline, all of the devices I have repaired by replacing the capacitors in the last year or so have all, without fail, had the failed devices branded as CapXon, who appear to make a significant number of the capacitors in electronic devices coming from China! Good thing everything is so cheap that it can be replaced.