It's my understanding that the answer to your question is based on technology advances affecting monitor display. I pulled the following from http://www.iconico.com/colorpic/web-safe-colors.aspx
This isn't research per se, but hopefully it will help with understanding.
"Back in the 1990s the graphics capabilities of browsers were very basic. To create webpages UX designers were limited to a reduced palette of colors for text, background colors and images. At the time the safest approach was to stick to a palette of 216 'safe' colors, meaning that the majority of browsers circa 1990 would have support for them. If designers ventured from the palette they would risk the browser providing an alternative, often with shocking results, orange being substituted with pink, or cyan being substituted with green.
After establishment of the W3C and browser innovations the websafe colors are a thing of the past. Modern designers need not concern themselves with the limited palette, and can use any color they want.... For web design on both desktop and mobile no limitations exist anymore in 2019."