The way many startups work is that they burn through money long before they make revenue. Investors put in millions and the company often operates at a loss for 3-8 years, before they suddenly IPO for billions.
So let's take this for an example:
Money in the bank = $3,000,000
Revenue for the year = $150,000
Costs for the year = $400,000
Profit = -$250,000
How much zakat would have to be paid on this? Although the company is not making money, there is a lot of money in the accounts.
What if some of the directors, investors, or major shareholders are non-Muslim? They would not appreciate so much being spent on zakat.