My mom works at a startup that was acquired by a big bank. She's a PL/SQL dev, and a majority of their business logic is implemented in PL/SQL on Oracle. After

My mom works at a startup that was acquired by a big bank. She's a PL/SQL dev, and a majority of their business logic is implemented in PL/SQL on Oracle. After the acquisition, the new bank execs decided to make a new initiative to rewrite the entire thing with "modern" technology. Lots of talk about MongoDB and microservices. After one year, and lots of revelations about how much of the business actually is implemented in PL/SQL, they have yet to even port one small part of the system to the new stack. It's becoming clear how little they actually understand about the requirements of the software, and why a system like Oracle was chosen in the first place. I'm also very confused about why people do this.