Modern Day The Twilight Zone Ideas

...suddenly, all local copies of web browsers disappear. The installers still exist on web servers, but no one has a browser installed any longer, so downloading a browser is difficult, but not impossible.

...suddenly, all compiled compilers disappear. We still have the source code for gcc, but no compiler with which to compile gcc. We have to bootstrap from scratch again. Years are lost.

...thinking of some more.