Cactoide looks great for one-off events - nice work! But it doesn't replace Meetup for recurring groups that need subscriptions, notifications, member management, etc.
The best alternative I've found so far is https://guild.host. Just launched Svelte Chicago on it (shameless plug - come join us!) and our first event yesterday went smoothly. Guild has some rough edges but a smart founder with the right priorities.
What's still missing, as TheAdamist mentioned, is discoverability. I think we need to separate meetup discovery from event management - an event-platform-agnostic registry/search that works across Guild, Eventbrite, Facebook Events, whatever. Hmm... might have just found our next Svelte meetup hackathon project.