Why some companies are still using legacy systems?

They are afraid of change. They one know one way to succeed. They like traditional things over innovations.

It is often difficult to convince and get adequate sanctions, importantly.  Secondly, the administrative and accounts sections are poorly staffed to take initiative for a change, because the transformation stage involves a considerable amount of work.  One more thing is that, there is a fear of loss of business secrecy to a good number of managements, often do not care for the innovative options on the presumption of considerable costs and investments which they do not want to part with.

Thank you for the invitation, but that Q is a bit complicated for me. I must agree with answers

Although legacy systems are very old and outdated, but these are still used (in many banks) because changing these systems is too risky and it cost much time, effort and money to introduce new systems.

Why some companies are still using legacy systems?

Legacy systems utilize outmoded programming languages, software and/or hardware that typically are no longer supported by latest ERP software.

Legacy systems are still used by some companies because they think a change over may cost them lot and potential risk of business interruption associated with the movement of data and key business processes to more advanced and contemporary technologies.

We have seen number of companies still heavily reliant on decades-old legacy systems. Further complicating the situation, many of these companies has been built through a series of mergers often must manage a variety of incompatible legacy systems inherited from their predecessor organizations.

In general, legacy systems tend to be given inadequate resources for their proper maintenance, even when an upgrade to contemporary technology is not being contemplated seriously. The blame must go to the decision makers in the organization and the non-technical executives who tend to assume that they can continue to run on the cheap, and underestimate the risks of taking this approach.