And really json in the database is just the more modern version of xml in the database, which of course SQL Server has supported for years. The problem with xml in the database was not a fundamental one, but rather an implementation issue -- where the json model in most solutions is some variation of toss-some-structured-data-in and then work with it, the XML model of SQL Server required significant poorly documented, confusing to implement configuration to work with in any meaningful way. It really killed the feature.
Personally I still think XML is superior to JSON, but it got usurped by the architectural astronauts who kept layering noise on it to the point of being unusable.