DX codes are a huge pain these days as a lot of new rolls of film, especially B&W don't have them, leading to a frustrating situation on cameras which won't allow you to manually set ISO (which is a huge number of sub-professional cameras).
This is what the end of the video is about, and there's even a reference to an available solution.
Which B&W stocks don't have them? Every B&W canister I've ever bought from Kodak, Fuji, and Ilford is DX-coded, and even the smaller manufacturers (like Foma) have them. The only B&W stock I've seen without a DX code is Astrum (which has come in a cheap plastic can every time I've bought it).
As the video points out, the big players mostly still DX code all their film, but many of the smaller, indie (or low-end) producers don't.
most of the small manufacturers--Ferrania P30, all the Foma films, I believe the Adox films as well. The Rollei films have DX, and like you said--Kodak, Fuji, and Ilford.