Cherries are extremely sweet, and are unusual in that they contain more glucose (52%) than fructose (42%). Their bright red colour comes from the carotenes and capsanthin (the E160 colourings) that are present in high quantities throughout the fruit.
Cherry flavour comes from a huge collection of aroma compounds produced naturally by the cherry. To make all of these compounds in the lab, then mix them together in the correct proportions would be ridiculously time-consuming and expensive.
When making artificial cherry flavourings, only the first two compounds are usually added: (Z)-3-hexenol and 2-heptanone. Artificial cherry flavouring thus tastes absolutely nothing like real cherries: it lacks most of the ingredients that give real cherries their delicious flavour.
It’s quite a different story with oranges and lemons, though. Most of the flavour of oranges and lemons comes from (+)-limonene and (-)-limonene, which, by themselves, smell like orange and lemon, respectively.