Market watchers like to follow trends because they are often a good indicator of what will happen next. The near future usually does look like the recent past, but not always. Sometimes we hit an inflection point and things veer sharply from the trend and that changes things in a way that can be truly transformational.
For example, for the first two decades of the 20th century, electricity and the internal combustion engine had limited impact, but around 1920 they became transformative and drove a 50-year productivity boom unlike anything the world had ever seen. Something similar happened with digital technology around 1995.