Are Master's becoming required for USA PhD programs? In the USA, many universities enroll PhD students with BSc degree. I think this is the classical scheme, which remained in the US universities. In many countries, it is almost impossible to enroll in a PhD program without MSc degree.

I am curious how is the trend for MSc programs?

At least in the USA, do more universities allow PhD enrollment with BSc degree or those allowing are shifting to MSc requirement?
At least in my field (mathematics), every US PhD program I know of accepts students with a bachelor's degree.  I see no sign of this changing.