Contractor estimates are just as prone to schedule slippage and cost overruns as anything estimated by software engineers. I doubt anyone's ever argued that giving wrong estimates is hard or impossible. Only that approximately correct ones are, and other industries seem to struggle with that just as much as software. Authors don't finish books by deadlines, so fans are left in the cold. Tunnels take twice as long and cost twice as much. Renovations take a year instead of 3 months and empty your bank account.

Saying "I don't know" is arguably more honest, even if it's not useful for budgets or planning.

> Contractor estimates are just as prone to schedule slippage and cost overruns as anything estimated by software engineers

I completely agree. That's why I chose that example: They're also awful at it, especially these days in North America in particular. But any contractor that tried to put in a bid claiming "it'll be done when it's done and cost what it costs" would not be considered professionally competent enough to award a multi-million dollar budget.