It's shareholders looking at a chart of AI extracted keywords that describe a movie and then comparing them to scripts with the same keywords. They only want to fund movies that have the same or greater return as previous films with the same basic descriptions or market awareness.

That was less of the case in between the 60s and 80s because:

• lack of comprehensive market data
• belief that audiences respond primarily to actors they recognize rather than plots or IP
• movies didn't have to appeal to broad international markets and could be about very specific themes (this is supposedly why comedy movies are less common)
• movies were less expensive to make and had less complications to get funding
• Movie producers were all high on cocaine and barbiturates 110% of the time and threw money around at random