Spending $0 on marketing is a short-term optimization. Don't confuse it with ability to scale. Scaling requires sales, mktg & infra.
Unsolicited advice to entrepreneurs: Stop going to conferences. Waste of time for almost everyone involved.
Lessons learnt: Don't drop your quality bar on hiring, even if takes longer. Don't hire for the sake of hiring (you will be pressured to).
OH: "The founder keeps giving his job away to really good people." Superb trait, essential to scaling a startup