That's a good point, I also think maybe anarchists efforts and groups tend to have a lower barrier of entry for baby leftists and newly radicalized people. Most anarchist projects I've been involved with (esp. mutual aid stuff) invite people to participate and help out regardless of their particular ideological tendency (as long as they're not fascists/chuds/assholes). That means people can jump in and start doing useful stuff without committing to a party line. This dynamic, of course, has it's own set of drawbacks, but I do think it's part of the reason why you see more anarchists out on the streets.

The infiltration angle is another good point - decentralized orgs can't be as easily shut down by co-opting/murdering/blackmailing/discrediting the leadership.