There is a big difference between middleware and applications.

Working for a large company, I know how complicated rolling out any new middleware is.

It requires agreement from security, production, infrastructure and the development teams.

It requires integrating into the existing monitoring solution, training the production folks in supporting it etc.

This means that :

1. You want to be sure the company will be there tomorrow

2. The cost of the license is not the dominating factor

When it comes to end user apps, you can afford to take a risk, and bet on the smaller players as the cost of making a mistake is much lower, and the license cost dominates.

That is why Atlassian have a business model that is attractive to large organizations, where as mid-range application server vendors don’t.