Block size is effectively infinite right now because they are nowhere near being full to the 500KB soft limit.
Bandwidth is NOT effectively infinite right now,...
-MarkM-
MarkM, I still read your posts because you embed enough useful feedback within your stream-of-consciousness padding to make it worthwhile, but it is a struggle at times.
Clearly bandwidth is finite, but the increase in propagation time between 50KB, 500KB or 5MB blocks is not very significant in a 10 minute time window. The increase in verification time seems to be the real limiting factor.
I used to support such idea, until I realize that a dynamic cap implies in an arbitrary formula, and that's an attempt to guess subjective demands and unpredictable supplies. It's impossible, and fortunately, not necessary.
The advantages are nice to have, not mission critical:
Politically, a cap is a less radical departure from the soft and hard block limit which people know about. Psychologically, it maintains a perceived need to add fees, and might price out SD-like flooding. It also prevents the chance that an unexpected monster block gets accepted and built on causing problems for some miners.