That’s a big problem with the standard in my opinion: standardization of new characters require submit a font for them but this font do not need to be open. So you have standardized characters that cannot be displayed without someone else implementing another font. That’s a lot of duplicate effort.
I'm not sure have over 100k glyphs in random fonts solves anything. I'm also not convinced fonts samples are something a character encoding should care about or try to standardize.
For practical use Googel's Noto font is under an open font license and covers so many glyphs it's collection is split into an multiple OTF files because of the 65k glyph limit per font. The goal of Noto is much the same as the one you propose - to have an open representation of every character (and in a consistent font).
> covers so many glyphs it's collection is split into an multiple OTF files because of the 65k glyph limit per font.
Not because of that. Out of the hundred Noto files, several are the same CJK characters with different country and Sans/Serif/Mono styles, and everything else combined would fit into a single file.
Even removing CJK, there are still more than 65,535 glyphs necessary to represent everything the the SMP and BMP less CJK. If you look in BMP without CJK, surrogates, and private use areas, you are looking at around 27,000 code points. If you look at the SMP (supplementary multilingual plane), there are around 90 blocks of 4096 code points assigned. That total is well over 65,535. And keep in mind many scripts also require unassigned glyphs which are not Unicode code points themselves. These unassigned glyphs count against the 65,535 TTF limit, though.
Sure, it would take two files to do everything outside CJK. What I said is still true, that everything covered by the non-CJK Noto fonts would fit in a single file (50k glyphs total).
My point is that you only need 3-4 files to cover Unicode. Noto is not split into a hundred different files for that reason, but for other reasons.
(Also the used space on the SMP is roughly 90 * 256.)
