It applies to all consumer items, which is just what computers have become. In fact there is probably a better life time line on some computers than say cars, or general electrical appliances. You're not going to scour the tech press for the latest toaster, but is you need some spare part for it, forget it. Most things these days are made on batch order, full stop. The next batch could be completely different, and is normally not the same quality as the first one anyway. There is of course a market for custom built equipment, but I for one am not in that range. On some stuff even the manufacturer of a follow up batch is different, and when the spares run out, that's it. Either you make your own or you buy a new one. It annoys me as well when I have to buy a new sound card just because the laptop manufacturers have deemed that PCMCIA is not worth the trouble of installing in new models. On the other hand I think we invest too much emotion in our computers and gear.
The only reason I am changing my computer is that it is so slow that it can't do Realband and Realtracks properly, let alone the Amp-Sim I bought. Otherwise it still runs perfectly after 6 years.

Chris