This article is a bit misleading. Yes, WP8 will no longer be supported. However, MS has already promised that most phones will be compatible with WP9, which means that you will be able to update your phone to the new OS and carry on with life. Sure some of the lower end devices may not get refreshes, but the higher end phones like the L920 and 8X will probably be fine through the entire WP9 lifecycle which will be another ~18mo which puts us at Feb of 2016. Considering the life of your average phone is ~2 years, that should be well beyond the useful product life cycle of mid to high end devices. If you currently have a cheap phone like the 720 then there is a chance you will not get the refresh, but then again it dosn't cost nearly as much to replace lower end devices, and users of more basic devices tend not to be so worried about having the 'latest and greatest' anyways.
Also, phones are not exactly like desktops. Being a closed environment it is not like the desktop where constant malware attacks mean that the minute your OS is no longer supported then you are completely screwed. It also does not mean that app providers, or the store itself, will simply dry up and disappear. You will still have a proper selection of apps, and (as long as there is a good sized WP8 user base) then app developers will continue to support their apps.
All in all it is no big deal.