Are there any Metafont projects going on?
Today, most of the use of these ideas is in drawing technical graphics. For instance, for his drawings Knuth uses MetaPost, which is very much like MetaFont but outputs vectors (there are some additions to take advantage of PostScript).
Another example of mp involves LuaTeX (briefly, TeX but where you can write in the scripting language Lua). The folks who have developed it have brought MetaPost in as a ready-made drawing library. See https://www.tug.org/TUGboat/tb29-3/tb93hagen-mplib.pdf for instance.
Finally, still another example of the use of these ideas is the stand alone graphics production program Asymptote https://en.wikipedia.org/wiki/Asymptote_(vector_graphics_lan... which aims to lift to 3D the algorithms that Knuth put into MetaFont to make beautiful curves. (I use this system.)
Another reason is magnify-ability, or zoom in-ability. Authors are annoyed when they produce a graphic, and then include it in a document, say expanded to 120% of its original size or shrunk to 75%, and it contains jaggie letters. Similarly, readers are annoyed to blow up a map and find that the town names are hard to read.
Still another is that one set of fonts will do for essentially all documents, so on your hard drive you don't need a set at 10 pts, another set at 11, etc. The space these take up is less of an issue than it used to be, but it is an administrative annoyance.
Another issue impacted me a lot since I put stuff up for download. You have to maintain a number of outputs for the dpi-ness of various output devices, so that people reading on a screen use a different output file than people using a printer. In addition, Knuth has settings called things like blacker to tune the output for the physical output device engine, so you may want to maintain output file versions tuned for a number of different vendor's devices. Besides, at some point printers just became vector devices.
Basically, the market has spoken.
And perhaps it would be possible to make a vector-outputting version, if this has already been done for MetaPost.
Letter & Spirit opens by describing a dialog between Knuth and Douglas Hofstadter ("Metafont, Mathematics, and Metaphysics"). For Hofstadter's essay, see https://core.ac.uk/display/15352994 or chapter 13 (p.260 & fwd.) of Metamagical Themas (https://archive.org/details/metamagicalthema0000hofs/page/n9...).
There is also Dexter Sinister's "A Note on Type" (https://www.sternberg-press.com/product/notes-on-the-type-ti...).
All this suggests that Knuth's Metafont work has ended up being a successful provocation regarding how it is possible to encode creative design and visual language.