- I2P can be attacked with far less resources than Tor;

Moot when $10k is probably enough to Sybil at least some small fraction of either of them.

- Tor is deeply researched and various attack types and problems have already been solved;

So if Tor is done, why don't you start writing grants to reseach, advance, and solve some of the undone, equally applicable, and necessary problem space of mixnets and other potential designs, instead of continuing to throw [government] money at Tor's curve of diminishing returns.

- Tor is larger as a network with more capacity, and more diversity;

Start advertising, using, analysing other types of networks then.

They also have different purposes so they cannot be directly compared on absolutely every feature

Why do so many reviews keep implying this copout, "B network doesn't have X feature therefore B sucks"... of course networks are different, unique features are not detractions they're just incomparable items, go compare and analyse the similar features then. Both Tor and I2P generally claim their non-exit modes to be anonymous advanced designs resistant to attack. Go compare and analyze that. If you don't like the results, go start new designs. Reviews can even conform features... users can actually torrent internally over both, and exit over both... analyze that. Many orthagonal features are modular ideas embeddable in any decent network anyway, so they're not necessarily unique, only a matter of doing it, if sensible of course.

- I2P is more oriented for traffic inside the I2P network (e.g. you cannot browse cnn.com anonymously via I2P).

Yes you can, you just have to find or be an exit outproxy service and configure it manually.

...

I would summaries the success of Tor over I2P with these points:

Government: Initialed the Tor design, put in Decades of $Millions of controlling interest funding, and programmed Marketing. Throw those kind of resources at I2P or any other network and they would be relatively equal contenders too. Throw Voluntary versions of those kinds of resources at any network, and it might be a bit more novel and free to go up against the backer of the "successful" one above.

...

- Tor has a modified browser which is a fork of firefox-esr called Tor Browser Bundle which is easy to click and run with Tor. I2P until now there is no official browser supporting it and user needs to do the configurations manually.

So stuff I2P inside TBB's work and call it IBB.