Okay, she is training Pari as a backup but she can still be part of the company post marriage. It is good that she is training Pari & later, Ansh but you can still be part of the operations. People work after marriage. I know that Mishti wants to be committed to her marriage but she can also be committed to her work at the same time. Women can handle their professional & personal life. Mauli managed her professional & personal life during her marriage & Kunal had no qualms about it. He ditched Mauli because he fell for Nandini (feelings are feelings but deception is deception).
Mishti is not shutting the company. She is training Pari to be her backup and take over her responsibilities. I guess you have not seen all the complete episodes.
P. S . 2 years for training someone is unrealistic. Pari already handles the creative aspects independently. She needs to get into Management decisions.