The only way to mass produce all the buttons in a complex layout (such as the 2000) at reasonable cost is by using "TV remote" button techniques. You can get "remote control keypad repair kits" using a special conductive "gunge" which claim to be tested to huge numbers of keypresses (how?) so they may help on out-of-warranty items but I have no experience of their usage.

Anyway, whilst I concur with the opinion that the failure is regrettable and should not happen on professional kit, we must try to remember that the 2k is a lot of gear for the money and therefore something has to give. Regrettably this is construction quality. The modern keyboard/synth is after all a computer with a custom user interface. Computer chips are cheap, custom interfaces are not.