I worked on a 300k LOC business basic application at one point.

The big question everyone was asking is how do you move to something else? Everyone wanted something else, they started writing new services on top of the old system, they had some ideas on where to go, but it just didn't seem like a gradual rewrite was possible.

And to be honest, a Greenfield rewrite just wouldn't work work for something this size with the resources they had. So it stayed in business basic.