In some cases it's OK. Many VC-pumped pre-IPO companies do that. As far as I understand the common strategy is to burn the surplus of investors' money on sales

In some cases it's OK. Many VC-pumped pre-IPO companies do that. As far as I understand the common strategy is to burn the surplus of investors' money on sales and marketing in order to pump up the company's revenue and thus capitalization. It is assumed that either the increased revenue will achieve greater economies of scale and will cover the high cost of sales and marketing. Or, if that didn't work, the marketing and sales expenses will just be rolled back and the company will continue growing organically, albeit with a lower capitalization.