There was plenty of that with the first .com implosion. Many e-commerce sites actually did have customers (eg. my sister swore by Kozmo.com), it's just that they got them by selling goods for less than they paid for them, and then the customer base dried up once they had to actually make a profit.
The big scam now is in customer acquisition: companies spend more in marketing than the LTV of a customer and make up the difference with VC cash. This is a little bit easier to hide: you have positive gross margins, explosive revenue growth, and the appearance of a sustainable business, but once you take your foot off the gas and stop spending VC money your existing customers churn away and you can't acquire new ones. Google and Facebook are also making out like bandits from this, and may get hurt significantly when the bubble bursts.
Yes, the cost of customer acquisition is certainly part of the current mess. While probably not strictly a gross margin issue, in practice it in effect is since that is very much a direct cost associated with the transaction.
There are certainly a lot of these upside down companies spending $100 to obtain a customer so they can sell a product for $70 that costs them $60 to make.
The cost of acquisition is also the cost of retention. I moved to DoorDash exclusively during the pandemic because of DashPass. Before that I was mostly UberEats.
UberEats would need to win me back, at least if they want me before I got back to the office.
As I usually only order food for lunch or whatever for one person, I found that I never hit the DashPass minimum. Maybe I'm just not a fancy enough eater.
The big scam now is in customer acquisition: companies spend more in marketing than the LTV of a customer and make up the difference with VC cash. This is a little bit easier to hide: you have positive gross margins, explosive revenue growth, and the appearance of a sustainable business, but once you take your foot off the gas and stop spending VC money your existing customers churn away and you can't acquire new ones. Google and Facebook are also making out like bandits from this, and may get hurt significantly when the bubble bursts.