Gnutella is itself a protocol. Most of the gnutella community work together to provide improvements that don't harm the network, don't cause unnecessary traffic, etc. in a most responsible way.
I don't see I2P doing that. For a start, it has tried to con people into believing it hides ip addresses when that isn't even possible. What else is it trying to con people with?
Why would the established single protocol programs deviate from their aims to do what some new kid on the block that knows little about community development desires. Why should everybody jump off what they've been doing to do what I2P wants to do. What is I2P anyway, an attempt at multinetworking, which it has been proved time & time again doesn't work properly. Somewhere along the chain, one network suffers. Just look at RAZA's lazy attempt & effect at joining the gnutella community has had. All networks need to be developed equally & without one particular network suffering as a result of more than one being used simultaneously. It simply doesn't work properly. A bit more research & you will realise what I mean. That's if you can be bothered of course. Yes some people have already seen other various program leeching techniques. Quote from the I2P site "People should not use I2P..." lol