Yes, because they are so outdated and no one wants to change as it costs money. Switch to 60Hz and solved
Similar thing is in Europe with 50i and 25p. BBC for example stopped transmitting movies as 50i (which causes some TVs trying to do not needed deinterlacing). They use 25p for movies and other shows originated in 25p and 50i for sport etc. In next few years they could even move to 24p for movies as basically all TVs at households will support it (it may not be true now).
Look at eg. Netflix. They use native for the show fps and this is how it should be. It's stupid politics to prevent eg. USA TVs support 50Hz (is it still true?). In Europe we have no problem watching Netflix at 23.976p, 24p, 29.97p, 30p etc. There is no real need (except political one) for any speed-ups, 3:2 pulldown, or conversion these days.
Does Netflix in USA work with 25p?
You have a problem with DF even if you natively shot for USA. Tell this for post houses in Europe which work to 25Hz. Then you end up with this stupid problem of 1 missing/too much frame ( or TC not starting at 01 or 10 if you do conversion).
At the end it's just metadata which has nothing to do with the actual video. When you collaborate you need to agree one type DF/NFD and stick to it and because broadcasting needs to work to real time they use DF, so you need to follow. Well, you don't have to during your work (you can even use frame number as reference). What counts is final delivery and this is where problems starts- some places want A, other B, another C, etc. and you end up with so many delivery versions. Sometimes difference is just DF vs. NDF flag, or even more 'stupid' things like 16bit vs. 24bit PCM or 10h based TC vs. 01h one
Trying to agree on 1 format proved to be simply impossible. It sort of works in UK now, spreading to some other European countries, but still far from having wide coverage.
Funny is that there is really no official 23.976 DF timecode ('normal' 24p applies), although some tools do have such a thing.
Legacy fact. In Poland for example they just turned off last analog transmission (some cable providers still had it on even when about no one was using it). I assume now it's gone for good. Main move to digital was actually in 2013.