Besides Microsoft, plenty of others thought UTF-16 to be a good idea. The Haskell Text type used to be based on UTF-16; it only switched to UTF-8 a few years ago. Java still uses UTF-16, but with an ad hoc optimization called CompactStrings to use ISO-8859-1 where possible.
A lot of them did it because they had to have a Windows version and had to interface with Windows APIs and Windows programs that only spoke UTF-16 (or UCS-2 or some unspecified hybrid).
Java's mistake seems to have been independent and it seems mainly to have been motivated by the mistaken idea that it was necessary to index directly into strings. That would have been deprecated fast if Windows had been UTF-8 friendly and very fast if it had been UTF-16 hostile.
We can always dream.
There are many other examples, and while some of them are derived from the ones you give, others are independent. JavaScript is an obvious one, but there's also e.g. Qt and NSString in Objective-C, ICU etc.
There really was a time when UTF-16 (or rather UCS2) made sense.