Sorry, but the version availability restriction is permanent due to reasons that are related to license and support restrictions from all of the third-party companies that provide the Adobe apps' default (included) plugins which provide the apps' functionality–in other words, Adobe was forced to completely withdraw all of those older versions of apps because the third-party companies had completely banned the availability of any no-longer-supported (or obsolete) versions of their plugins, and by extension any version of the apps from every single software company that included such obsolete versions of the plugins.
Adobe could have reverse-engineered or included plugins of its own creation, but that would have astronomically increased the subscription costs to stratospheric levels (as in the cost of a single-app subscription would have cost hundreds or even thousands of dollars per subscriber per month instead of the current $25 per month (including taxes).