Pilots tell me the 73 flies well but the cockpit was and is poorly laid out. From a business perspective, an aircraft that makes money is not likely to be curbed before a really good replacement is ready, as ryane946 says above (nice post). I personally work on systems for this airplane, and I would say from where I am that it will be in production for at least ten more years, and even then, the airframes will remain in service for many additional years.