Only the 32-bit versions. And those appear to be dying out (even cheap low-end laptops nowadays come with 4 GiB of RAM and a 64-bit version preinstalled).

But MS-DOS and Win16 isn't software anyone still have to deal with when making new content because the software isn't used by anyone to deal with any content, only legacy software that won't hurt anyone. It's isolated.

But a browser doesn't get stuck in time like a OS does when it dies, they don't surf on the same Web as when they were popular while an old outdated OS still runs its old outdated software just fine. MS-DOS and Win16 also weren't garbage, IE6 is.

Windows 7, at least the 64bit version, will not run Win16 programs. Ran into that limitation trying to install some old software from the Win98 days that was still using essentially a Win3.1 installer.