With the advent of sound design, trailer music, and more contemporary sound sources making their way into mainstream music since the late 1900's, the orchestra has taken a back seat in favour for more 'modern' styles of music.
However, the orchestra never completely disappeared, and more recently, composers started to realize the expressive potential and beauty that the orchestra can provide. Therefore, it's no surprise that there have been an explosion of orchestral-based sample libraries on the market over the past decade.
As technology has become more affordable, composers and producers around the world now incorporating elements of the orchestra into their own music.
The downside is, many of them have no idea how a real orchestra works.
What are the timbral and playable ranges of the orchestral instruments? What combination possibilities lie within each instrument family? Do the brass sit naturally with the woodwinds, or do they need to breathe?
What ends up happening is that many tracks sound unrealistic, unbalanced, and messy, due to a lack of orchestration and arranging knowledge. Sample libraries are so forgiving, and you can get away with anything in a DAW.