• If the room acoustics are bad, or there is too much "foreign" noise, even close miking may not result in a good recording, particularly if the microphones are not really close to the sound source of the instrument, or you are trying to capture the sound of a group of instruments with a single microphone. You may well discover that you cannot get a good recording.  After all, acoustic instruments are just that, and the microphone is picking up at least some of the sound of the recording space as well as the instrument.  There are various recording and post production techniques and equipment that can "clean up" dirty tracks but all of them leave various artifacts which may well be worse than the original recording, and most of them take a lot of trial and error to apply successfully.
  
  
• The successful multitrack recording of separate tracks at different times, while allowing for better isolation and the ability to do individual track retakes, requires musicians with experience playing while listening to the previous tracks on headphones. This can be particularly problematic for recording the first few tracks, where the musician is essentially soloing, while playing to a "click track" and imagining what the rest of the band will sound like.  Sometimes. bands will do a quick track with everyone present to use as a "scratch track"  to listen to while recording their individual tracks.  Many musicians find this difficult to do successfully without a lot of prior experience.  In any event, the recording will probably loose the "vibes" between the musicians that make for a memorable recording.  Possibly not as important with pop music, but vital with good jazz, and in many cases steelpan.
  
  
• The successful post production mix and processing can take far longer than the original recording.  In fact problems with the original recording that were not noticed during the recording process may require doing retakes of one or more tracks.
  
  
• It is very easy during the mixing and processing process for the ears to become fatigued.  The mix that sounds perfect tonight can sound awful with the light of a new day.
  
  
• It is vital to have good monitor speakers and amplifiers during the mixing process.  Otherwise your mix may well be compensating for your poor monitors, and sound bad when played with a better reproduction system.  (This applies to orchestral recording also, but since it is common to "process" the individual tracks of close miked multitrack recordings more than orchestral recordings, it becomes more critical when multitracking.)
  
  
• It takes far more equipment which takes geometrically longer to set up and adjust if you are close miking a session with any significant number of microphones.  Close miking can greatly increase the costs involved, either for purchase or rental.
  
  
• Finally, if you spend significant time checking the individual tracks of a take and readjusting microphones or equipment, the musicians may loose any vibe or spirit at the session between takes.  If the setup is at all complicated, it may be advisable or necessary to hold a technical rehearsal with the entire orchestra, often a matter of considerable expense and further tiring the musicians.  Tired, bored musicians do not usually make for good music. 

 Most recordings of "pop" music have been close miked and multitracked, since at least the mid 1960's.