This trend started when the first video-capable full-frame DSLRs appeared on the scene about a decade ago, and they led to a mixing of the visual language of photography and filmmaking. Combined with the fact that camera lens developers are working hard to remove flaws from their products, making their picture more and more perfect, but also removing any character a lens can have.
The classic Super35 frame size is more akin to APS-C in digital photography, whereas the new top tier cameras use full frame sensors, which are 1.5x larger in diameter.
The larger the sensor, the more bokeh you get, with a shallower depth of field.
Modern tech for focus pulling allows for extra shallow depth of field even if the actors and the camera are moving. Something that would have been mostly out of focus footage 30 years ago can be easily shot with a small crew.
Large aperture photography lenses and large sensor also means much better low-light capabilities. Which means you can shoot with less studio lights, in a much lighter setup with less crew, less planning etc.
Blurry backgrounds also allow for cheaper sets.
Which means the cheaper the production budget is, the more likely they'll go with shallow depth-of-field shots.
And we the viewers will inevitably connect the cheapness of production with these visual cues.
In contrast, when an older movie had shallow depth of field scenes, those were expensive shots that had to be carefully planned, and painstakingly executed with "flawed" optics which gave them a lot of character.
The classic Super35 frame size is more akin to APS-C in digital photography, whereas the new top tier cameras use full frame sensors, which are 1.5x larger in diameter.
The larger the sensor, the more bokeh you get, with a shallower depth of field.
Modern tech for focus pulling allows for extra shallow depth of field even if the actors and the camera are moving. Something that would have been mostly out of focus footage 30 years ago can be easily shot with a small crew.
Large aperture photography lenses and large sensor also means much better low-light capabilities. Which means you can shoot with less studio lights, in a much lighter setup with less crew, less planning etc.
Blurry backgrounds also allow for cheaper sets.
Which means the cheaper the production budget is, the more likely they'll go with shallow depth-of-field shots.
And we the viewers will inevitably connect the cheapness of production with these visual cues.
In contrast, when an older movie had shallow depth of field scenes, those were expensive shots that had to be carefully planned, and painstakingly executed with "flawed" optics which gave them a lot of character.