So Ripple's business plan is to build this bridge and help make itself obsolete. Why do I doubt that?
When Apple builds a new iPhone, they make the old ones obsolete.
That analogy fails in so many ways.
Apple's business plan in creating the iphone was not and is not to "create a bridge." Show me a speech by Steve Jobs where he said that the reason to adopt the iPhone was as some sort of bridge.
Apple's business plan in creating each iPhone is to meet a current demand, a demand that they expect to be temporary. You can view each iPhone as a bridge that meets people's present needs and lays the groundwork for future products that meet their changing needs in the future.
I wouldn't take this analogy too far. But every business plan is a temporary thing. Ripple Labs doesn't expect to be doing the same thing forever and its current revenue model will almost certainly become obsolete at some point. That may mean Ripple Labs does something else. It may mean Ripple Labs develops the things that make it obsolete. You can only plan so far ahead.
If your point is that we're likely to explore other revenue models before our current one runs out, then I would absolutely agree with you.