Budgets for television program production are constantly being trimmed, with the result that there is less money available for music. So where it is still common for a film soundtrack to be recorded using an orchestra (plus guitars, synths and samplers as required), TV music is mostly made by lone composers working in home studios.
But the odd thing is that if you watch a well-made program, a documentary for instance, then you will hear the sound of an orchestra, but it isn't an orchestra. So how is this achieved?
The answer is modern digital instruments, including software instruments. Although it has long been possible to sample orchestral sounds, it wasn't until the introduction of the Roland JV series of sample playback/synthesizer instruments and rackmounts that you could play orchestral sounds from the keyboard and they would sound convincing.
To be honest, this wasn't down to the instrument itself, but to the sample library it employed, available in hardware add-on modules rather than disc.
The next milestone was the Nemesys GigaSampler, which is now known as the Tascam GigaStudio. This software used a clever buffering technique to allow sample libraries of virtually unlimited size, rather than merely what could fit into available RAM memory.
And now, sample libraries have grown; there are more instruments and software instruments to make use of them. It is possible to produce extraordinarily convincing orchestral sounds, textures and arrangements without actually employing an orchestra, or hiring a studio of the necessary size.
But what often gives the game away is the fact that the sounds are being played from a keyboard. It is easy to play certain patterns on a keyboard, but they wouldn't necessarily be playable, or desirable on, say, a violin.
So a lone composer hammering away on a keyboard is likely to produce orchestral sounds, but not a believable orchestral arrangement.
It is also true to say that although these new libraries and instruments are very good, they can't do everything that an orchestra can do. Some things just don't work. So a composer would tend to go for musical lines and structures that do work, and shy away from anything that gives the game away.
So there is no doubt that a real orchestra is superior to the sampled and sequenced alternative. But the advantage has become smaller, and TV production companies, often, are just not prepared to pay the extra.