In Mathematica versions prior to 11.2 or 11.3 (not sure at the moment) it was possible to select the default format type of new output cells via Preferences -> Evaluation. In particular, it was also possible to change it from StandardForm to TraditionalForm, which I personally like very much.

From the point of view of a package developer, TraditionalForm typesetting allows to make the output more visually appealing and close to what people see in books and papers. And it is also quite fun to develop TraditionalForm typesetting rules. I understand that sometimes it might be confusing to new users, but the StandardForm is often just too inconvenient to read, so I actually only use it to copy and paste expressions.

However, in more recent Mathematica versions this option was removed from the preferences and is now "hidden" in the Option Inspector. A new user not aware of the existence of TraditionalForm would now always see only the StandardForm output.

Does someone know why this happened? Were there perhaps some recent statements from WRI regarding the future of TraditionalForm? I truly hope that it is not going to become deprecated or something like that.

• Somebody from WRI might be able to respond, but you can imagine that the question as it stands requires insight that our community of users simply would not possess, and is likely to end up closed for a host of reasons. Nov 21, 2019 at 0:03
• You may have more luck on Wolfram Community where more WRI developers answer questions. Nov 21, 2019 at 8:01

TraditionalForm isn't going anywhere. In fact, the new Wolfram Alpha Notebook Edition defaults to TraditionalForm output. As one the lead developers for typesetting, I can assure you nothing has been ripped out, and we continue to add TraditionalForm rules as appropriate. However, we enter more and more areas where there is no "traditional" formatting to imitate, so there aren't always special TraditionalForm rules.