Now you have to find trainers($) to "update" 200 people's skills, you need to find room/equipment to teach them the new software($$). Create time away from paying work for the training($$$), pay employees to be trained($$$$). The company has to eat the lost productivity and disruptions due to training($$$$$). Pay out for learning materials($$$$$+), pay to have all those power point presentations with the company logo($$$$$++). So now everyone is finally trained to the new standard, but the company still has to deal with the lost productivity due using the "new" system. All the problems due to forced training, and the employees you had to fire or who quit/retired instead of being trained. And the costs go on and on for years, until the company adjusts.
A good example of this is a major Canadian bank the I worked for in 2005; the bank was still using DOS applications running in a DOS Box under NT 4, because the apps worked. It was easier and cheaper to train new employees to use the DOS apps, then to write a "Windows pretty" front end that gave the same functionality. The bank did change to XP in 2007, but all those apps were still there and could be called up in a DOS Box.
And one of the major reasons is that a teller that has been working in the same branch for 40 years; does not need to be retrained to do the job. The teller is doing their job just fine with the same software they always used, once that teller quits or retires a new person can be trained to use the XP front end.