I cannot be sure but there are clues ... (The fact that this page crashes after ten seconds on mobile chrome being the first one :))

because with vibe coding, one can easily generate thousand lines of code in a short period of time. If we do this in parallel, merging the changes, resolving merge conflicts will be a nightmare. Unless, the agents work on completely isolated modules, but that's rarely the case?

Edit: yes it was: https://x.com/amanrsanger/status/1983581288755032320