This issue persists as of today (March 2019), in Python 3.7.2 (64 bit) running on Windows 10.  I gather from the comments that fixing it is no trivial matter, although I don't fully understand why.  The hang of "several seconds" that was originally described is at least 30 seconds on that platform -- I'm not sure when it would clear, as I didn't have the patience to wait it out.

https://stackoverflow.com/questions/55109076/python-tempfile-temporaryfile-hangs-on-windows-when-no-write-privilege

It seems to me that a genuine naming collision would be pretty rare -- at least for the (fairly common) use case I'm dealing with, trying to check where the directory is writeable or not.  Would it make sense to at least set a default number of collision-retries that is significantly lower?  Say, between 3 and 10, instead of the system max?