How many unencoded characters still exist? I've been wondering: How many unencoded characters still exist?

I realize this is probably mostly speculation and it would be quite hard to pin down an actual number. Language Log, though, did post a blog entitled, How many more Chinese characters are needed?, in the article they write:


  This month, the Chinese government plans to introduce codes for some 3,000 Chinese characters as part of a grand project, known as the China Font Bank, to digitize 500,000 characters previously unavailable in electronic form. Until now, only 80,388 characters have been encoded in the international computing standard, Unicode.


But the comments mention a few issues with what was quoted in the NYT opinion piece. Endymion Wilkinson also broke down the five k:


  It aims to lay down a more solid basis for the study of Chinese characters by encoding about 100,000 ancient Chinese scripts characters; 300,000 kaiti forms; and 100,000 minority scripts characters to give a grand total of 500,000


Any ideas?
GlyphWiki.org contains 580’000 characters. 92’856 are encoded. You can do the math. However, it will be wrong, as most of these characters are trivial alterations of those already encoded, and thus ineligible for a separate encoding.

So, instead let’s look at the pipeline of next encodings. Extension I (officially, Working Set-2017) is being finalized right now (and can be browsed at https://hc.jsecs.org/irg/ws2017/app/) to around 5’000 characters. Among these:


PRC has hundreds to offer, many of these Zhuang;
Taiwan is almost exhausted and sends only a small number of chemical characters;
ROK has hundreds, but much smaller number, of historical characters;
Vietnam still has some Nom;
However, the UK/UTC selection of scholars is still going strong, providing, say, data from dialect dictionaries.
To say nothing of Buddhist characters.


Most importantly, ROK and Vietnam offerings are approaching conclusion, and it is unlikely there will be substantial extensions thereof. Unless some new surnames or geographical locations are discovered, Japan and Hong Kong have no more intention for encoding.

I expect the following encodings after I to be in number of thousands, not tens of thousands, and the scholarly UK/UTC extensions be the lion’s part of it.