If you pour cold tea on your only laptop at 7pm just before a gig, buying and setting up a new laptop could prove difficult.
Your hypothetical is not consistent with the redditor's complaint. The redditor implies that he can survive without the laptop for a day or two--but things become problematic around five days, so I think @tiew9Vii's point-of-view is reasonable.
It's also consistent with my situation. I make my living off of my laptop. I don't have a spare, which I think would be a financial waste. If my laptop suffers a catastrophe, I will rent/purchase a stop-gap device. I can take a productivity hit for the 24-48 hours it takes me to get back up to speed.
The general idea is that when it comes to business, contingency planning and backups (data and hardware) are considered to be requirements.
It’s common to get given temporary mobile phones if in for manufacturers warranty repair so why not offer it for laptops?