3. Integration - In many software systems, once they get large and expansive enough, it looks something like this.
Software bundle does process a,b,c,d, they are all tied together.
A competitor has to bite of a small enough chunk to make it feasible, so they try to create processb, for example, better than the monopoly. They do, they do it 2x better, for 1/2 the cost!! A clear winner. Yet it's 100% useless, and unable to compete. Because it can't know how to talk to processA and C efficiently, no customer would be able to use it. This goes on an on, to costs of changing systems, training costs, expertise, etc. It effectively prevents competitive market entry this way.