I think the reason PayPal doesn't get a mention is that they don't need to - they know the business they're in and so will the people reading the release that matter.
Also, it's not necessarily a positive thing to make any comparisons between their aspirations and PayPal's business - for three reasons I can think of right now:
1. Visa would not want to have the thoughts of prospective clientele limited to the PayPal model, especially if they have more to offer.
2. Visa certainly would not want to tarnish their image - which the market would instantly perceive at the mere mention of being in the same field as PayPal.
3. Some other legal requirements and/or the potential for PayPal to sue Visa. (Why? No idea, but over there, what reason do they need?)
It is a topic of great interest, though - isn't it?!!