1) I agree that the moat for these companies is thin. AFAICT, auto-complete, as opposed to agentic flows, is Cursor's primary feature that attracts users. This is probably harder than the author gives it credit for; figuring out what context to provide the model is a non-obvious problem - how do you tradeoff latency and model quality? Nonetheless, it's been implemented enough times that it's mostly just down to how good is the underlying model.
2) Speaking of models, I'm not sure it's been independently benchmarked yet, but GPT 4.1 on the surface looks like a reasonable contestant to back auto-complete functionality. Varun from Windsurf was even on the GPT 4.1 announcement livestream a few days ago, so it's clear Windsurf does intend to use them.
3) This is probably a stock deal, not a cash deal. Not sure why the author is so convinced this has to be $3B in cash paid for Windsurf. AFAIK that hasn't been reported anywhere.
4) If agentic flows do take off, data becomes a more meaningful moat. Having a platform like Cursor or Windsurf enables these companies to collect telemetry about _how_ users are coding that isn't possible just from looking at the repo, the finished product. It opens up interesting opportunities for RLHF and other methods to refine agentic flows. That could be part of the appeal here.