In both cases the vendor suggested that it was the integration of some of the standalone data protection add-ons we see today like deduplication, continuous data protection (CDP), strong VMware protection and replication that would push you over the edge and get you to buy their product. Despite this, all the companies that offer these alleged point solutions like Data Domain, Exagrid, Vizioncore, PHD Virtual, appAssure, InMage and others continue to enjoy increasing business.
Part of the premise to move to an all-in-one solution is that the backup software vendor has the backup process nailed. Based on almost every survey or study I see, backup and restore failures are still extremely high and in fact are the reason why there is such a large data protection add-on market. You are looking for anything you can do to make your backup and data protection pains go away. Obviously backup applications by themselves are not cutting it.
The next challenge is that the solutions that would be integrated into the backup application need to be almost as good and complete as these standalone solutions. They can be slightly less capable and maybe pick up a few consideration points because of integration, but they have to be close. By and large, I don't think this is happening -- most of the integrated solutions don't hold a candle to the standalone solutions.
The second reason is it typically is easier to fix an immediate problem with a less comprehensive solution. If you like your backup application but wish it did a better job with dedupe, CDP, VMware or replication, it is probably less daunting to fix that one hole.