Thesis: Investments into IT infrastructure and, likewise, business infrastructure software, do not possess any intrinsic value on their own.
In my (German) blog entry http://bit.ly/Ma5LDm at www.enterprise2punkt0.at I argue that one has to use the same set of tools to justify investments into a BPM platform like ARIS (but also into an Enterprise Service Bus, a DMS and other software commonly called "Business Infrastructure Software") as for "classic" IT infrastructure such as servers and other hardware.
This essentially entails that there are only three value drivers for business infrastructure software:
a combination of these two entries
In my blog - as of this point in time unfortunately only available in German - I give some more examples and add a little bit of structure to this thought.