coelacanths are still around and they have not "evolved".200 coelacanths were caught many times in different parts of the world.
You making this statement as if it is relevant to something being (or being a representative) of a transitional shows one of the common misunderstandings.
You are a descendant of your grandfather and are different from him. The fact that he may still be around doesn't make you any less a decendent from him nor make him less a transitional form between your great, great grandfather and yourself.
If a population of amphibians split into a group which, over time, evolved into reptiles that doesn't say that the rest of the population couldn't have stayed as amphibians.
Fish are highly successful forms. The fact that there are environments where
some fish might do well if they have some ability to survive out of water doesn't say that ALL the fish have to abandon the ocean.
Somewhere back there fish that were like the coelacanths took a turn toward the land. That doesn't mean that the entire population was in the same place and under the same environmental pressures.