Which SAP instance are you suggesting to connect to, would I be so inclined? How would you start creating things for SAP vs. for example Facebook (or G+ now, or the Mac Store)?
There's a set of companies on the one side with broad public appeal and lots of ways to hack and tinker.
On the other side you have a behemoth with an army of suits, costing you a couple of limbs for every move - and it's completely useless for the layman.
Note the last statement. If you don't run a business and are in a couple of related positions you just don't care about that stuff. If you are you're probably using and either loathing or loving it. But even if they had SAP in 99% of all companies, they'd still only reach a limited subset of people.
That said, I completely agree that there are (apparently) higher barriers to entry to SAP and it mystifies me why this would be in their best interests -- I assume in some sense it is the security of the "gated community," where one knows that if one engages a SAP consultant he/she has already been vetted in some fashion.
This sort of approach (which I find typical of Germany) leads to a high average but a real handicap when it comes to innovation. But then again if you are doing something very well it is easy to make money hand over fist and then use that money to buy the latest greatest new sauce once it is ready (which is what SAP has done here with this acquisition).
Maybe there should be another version of that silly Gartner diagram where the axes are "importance" and "interestingness" - SAP would be high importance and low interestingness .